Oct/Nov 2024

Which SI base units are used for the moment of a force?

Turning effects of forces

A lift (elevator) has a passenger car held up by a cable that passes over a light, frictionless pulley and is attached to a counterbalance. As the passenger car moves up, the counterbalance moves down. The table lists some masses: - passenger car: $520\,\text{kg}$ - counterbalance: $640\,\text{kg}$ - passenger: $80\,\text{kg}$ What is the magnitude of the acceleration of the car when it carries only one passenger and the pulley is free to rotate?

Momentum and Newton's laws of motion

A ball with mass $m$ is at rest when it is struck by a bat. After impact, the ball moves away from the bat with velocity $v$. The bat stays in contact with the ball for a brief interval $\Delta t$. What is the average force exerted by the bat on the ball?

Momentum and Newton's laws of motion

A disc with mass $M$ travels over a horizontal surface that is frictionless at a constant speed $u$. It then collides with a second disc of mass $4M$, which is initially at rest. The diagram gives a plan view of the two discs’ motion before and after the collision. Determine the initial velocity $u$ of the disc of mass $M$.

Linear momentum and its conservation

An object is released from rest on the Earth from a height of $2.0\,\text{m}$. The same object is released from rest on the Moon from a height that is twice as large. The acceleration of free fall on the Moon is about $16\%$ of the value on the Earth. Assume that no resistive forces act on the object. What is the ratio $\dfrac{\text{speed of the object just before hitting the surface on the Earth}}{\text{speed of the object just before hitting the surface on the Moon}}$?

Equations of motion

The graph illustrates the variation of velocity $v$ with time $t$ for a bungee jumper. At which point is the bungee jumper briefly at rest, and at which point does she have zero acceleration?

Equations of motion

A solid sphere, with a density lower than that of water, is kept fully submerged in water several metres below the surface. The water has uniform density. The sphere is then released. At once after release, the sphere moves upward. Which row states how the magnitudes of the upthrust on the sphere and the resultant force on the sphere change as it rises?

Density and pressure

A bar with uniform density has a weight of $200\,\text{N}$ and a length of $4.0\,\text{m}$. It is hinged freely to a wall at one end. The bar remains horizontal and in equilibrium because of a cable fixed at a point $0.50\,\text{m}$ from the far end. The cable makes an angle of $35^\circ$ to the horizontal. Determine the tension $T$ in the cable.

Turning effects of forces

Each diagram depicts two equal forces applied to a metre rule. Which diagram shows forces that form a couple and have zero resultant force?

Turning effects of forces

A ball of mass $m$ is projected upwards to a height $h$ in air with initial velocity $v$, as illustrated. The effect of air resistance is negligible. The acceleration of free fall is $g$. How much total work is done by the gravitational force on the ball as it travels from P to Q?

Gravitational potential energy and kinetic energy

A spring with spring constant $30\,\text{N m}^{-1}$ hangs vertically from its upper end. The spring follows Hooke’s law. At the start, it is neither compressed nor extended. A mass of $0.50\,\text{kg}$ is attached to the lower end of the spring. The mass is let go from rest and drops. Frictional forces may be ignored. During the subsequent motion, what is the greatest extension of the spring?

Energy conservation

Which of the following statements about vector quantities is correct?

Scalars and vectors

A wire of original length $L$ and cross-sectional area $A$ is subjected to a tensile force $F$, causing an extension of $x$. The wire follows Hooke’s law. What expression gives the Young modulus of the material from which the wire is made?

Stress and strain

A wire is extended by a force that rises steadily. The force-extension graph for the wire is shown. Which statement has to be correct?

Elastic and plastic behaviour

A spring has an unstretched length of $0.30\,\text{m}$ and a spring constant of $400\,\text{N m}^{-1}$. An object is hung from the spring, and the spring is stretched within its limit of proportionality. Its length then becomes $0.50\,\text{m}$. What is the elastic potential energy stored in the spring?

Elastic and plastic behaviour

A wire is made up of a $3.0\,\text{m}$ section of metal X joined to a $1.0\,\text{m}$ section of metal Y. The wire has a constant cross-sectional area throughout. When a load is suspended from the wire, metal X increases in length by $1.5\,\text{mm}$ and metal Y increases in length by $1.0\,\text{mm}$. The same load is then suspended from a second wire with the same cross-sectional area, but this time it contains a $1.0\,\text{m}$ section of metal X and a $3.0\,\text{m}$ section of metal Y. For both wires, the extension stays within the limit of proportionality. What is the total extension of this second wire?

Stress and strain

The graph indicates how displacement changes with distance for a progressive wave at a single moment in time. The period of the wave is $91\,\text{ms}$. What can be deduced about the wave?

Progressive waves

In which sequence are the electromagnetic waves arranged from the shortest wavelength to the longest wavelength?

Electromagnetic spectrum

A wave’s frequency is $5\,\text{GHz}$. What is the wave’s period?

Progressive waves

Three statements about two progressive waves are given below. 1. The waves share the same frequency. 2. The waves share the same amplitude. 3. The waves are produced with a constant phase difference. Which statements must be true if the two waves are coherent?

Progressive waves

Waves P and Q have equal amplitudes. At point X, the waves arrive in phase and combine to produce a resultant wave of intensity $I$. The amplitude of wave P is then doubled. What is the intensity of the new resultant wave at X, expressed in terms of $I$?

Interference

Radio waves are able to be polarised, whereas sound waves are not able to be polarised. Which statement explains the reason for this?

Polarisation

A rectangular block’s material density is found from measurements of its mass and its linear dimensions. The measurements and their uncertainties are given below. mass $= (25.0 \pm 0.1)\,\text{g}$ length $= (5.00 \pm 0.01)\,\text{cm}$ width $= (2.00 \pm 0.01)\,\text{cm}$ height $= (1.00 \pm 0.01)\,\text{cm}$ The calculated density is $2.50\,\text{g cm}^{-3}$. What uncertainty should be assigned to this value?

Errors and uncertainties

Light of wavelength $\lambda$ is directed normally onto a diffraction grating that has a total of $N$ lines across width $w$. A second order maximum is seen at a diffraction angle of $\theta$. What is the value of $N$?

The diffraction grating

Kirchhoff’s second law follows from a fundamental principle. What is that principle?

Kirchhoff's laws

The diagram illustrates a circuit containing a light-dependent resistor (LDR). The ammeter shows a current of zero. What is the resistance of the LDR?

Practical circuits

A torch has three lamps arranged in parallel, and it is supplied by a cell with electromotive force (e.m.f.) $3.0\,\text{V}$ and negligible internal resistance. The power dissipated by each lamp is $0.60\,\text{W}$. What current flows in the cell?

Potential difference and power

A cell that has internal resistance is joined to a light-dependent resistor (LDR), a fixed resistor and a voltmeter, as shown. The voltmeter reading rises. Which quantity falls as the voltmeter reading rises?

Potential dividers

The circuit diagram shows a cell whose internal resistance is negligible. The energy transferred per unit charge in moving charge all the way around the circuit is $E$. The potential difference (p.d.) across X is $V$. The cell is then exchanged for another cell with the same electromotive force (e.m.f.) but with significant internal resistance. What is the effect on $E$ and $V$ when the cell is replaced?

Potential difference and power

For the circuits illustrated, the batteries are identical and each has negligible internal resistance. Every resistor has the same resistance. The diodes have zero resistance while conducting and infinite resistance when not conducting. In which circuit is the battery current largest?

Practical circuits

A potentiometer circuit is employed to find the electromotive force (e.m.f.) $E$ of a cell. The setup also contains a second cell with e.m.f. $1.5\ \text{V}$ and internal resistance $0.50\ \Omega$, which is joined to a uniform resistance wire $XY$, as shown. The resistance wire $XY$ is $0.96\ \text{m}$ long and has a resistance of $0.50\ \Omega$. The sliding contact Z is shifted along wire $XY$. The galvanometer shows zero when the length $XZ$ is $0.64\ \text{m}$. What is the value of e.m.f. $E$?

Practical circuits

Which particle is not classified as a fundamental particle?

Fundamental particles

The isotope fluorine-18, $^{18}_{9}\text{F}$, decays by $\beta^+$ emission to produce a stable isotope. How many neutrons are present in the nucleus of the stable isotope?

Atoms, nuclei and radiation

What would be a reasonable estimate for the volume of a single page in this examination paper?

Physical quantities

Which statement is the correct one?

Physical quantities

A body is launched from level ground with speed $u$ at an angle $\theta$ above the horizontal. It returns to the ground after a time $t$ has elapsed since launch. Take air resistance to be negligible. Which statement does not describe the motion of this body?

Equations of motion

A traveller covers a total distance of $200\,\text{km}$ on a motorway and completes the first $90\,\text{km}$ at an average speed of $80\,\text{km h}^{-1}$. What average speed is required for the rest of the journey if the traveller is to arrive at the destination in a total time of $2$ hours $60$ minutes?

Non-uniform motion

A car with mass $1200\,\text{kg}$ has momentum $18\,000\,\text{kg m s}^{-1}$. What is the car’s kinetic energy?

Momentum and Newton's laws of motion

A ladder rests on icy (frictionless) ground and is leaning against a rough wall. The moment it is released, it starts to slide. Which diagram shows the directions of the forces $P$, $W$ and $R$ acting on the ladder while it is sliding?

Momentum and Newton's laws of motion

A toy parachute is released from a bridge and descends vertically through the air. The graph plots the distance travelled by the parachute against time. Which part of the graph indicates when the parachute is at terminal velocity?

Non-uniform motion

A physical quantity has both a magnitude and a unit. Which row does not present a correct pairing of a quantity and its unit?

SI units

Two train carriages, each of mass $5000\,\text{kg}$, move towards each other on a horizontal frictionless track. One carriage is moving at $2.00\,\text{m s}^{-1}$ and the other at $1.00\,\text{m s}^{-1}$, as shown. They collide and stick together. Calculate the kinetic energy lost during the collision.

Linear momentum and its conservation

What one condition has to be satisfied for an object to be in equilibrium?

Equilibrium of forces

A kite is shown in equilibrium at the end of a string. Three forces act on the kite: its weight $W$, the tension $T$ in the string, and the wind force $F$. Which vector diagram shows the forces acting on the kite?

Equilibrium of forces

Four forces act around a point $P$, as illustrated. The forces lie in one plane and create no resultant moment about point $P$. What is the distance $XY$?

Turning effects of forces

A block of lead is rectangular and has a density of $1.13 \times 10^{4}\,\text{kg m}^{-3}$. Its side lengths are $12.0\,\text{cm}$, $15.0\,\text{cm}$ and $10.0\,\text{cm}$. What maximum pressure can the block produce when it is resting on a table?

Density and pressure

What does power mean?

Potential difference and power

A model car moves in a straight horizontal path with a constant velocity of $12\,\text{m s}^{-1}$. The power supplied to the engine is $800\,\text{W}$. The engine has an efficiency of $60\%$. What is the total horizontal resistive force acting on the car?

Energy conservation

Which statement expresses the principle of conservation of energy?

Energy conservation

A $50\,\text{kg}$ barrel is pushed up a frictionless plank of length $3.4\,\text{m}$ so that it is loaded onto the rear of a lorry that is $1.6\,\text{m}$ high. What is the least work done?

Gravitational potential energy and kinetic energy

What is one unit used to measure stress?

Stress and strain

A small car is moving through a town. What would be a sensible estimate for the car’s kinetic energy?

Gravitational potential energy and kinetic energy

The graph plots stress against strain for three wires that have identical linear dimensions but are made of different materials. Which statements are correct? 1. The extension of P is roughly double that of Q for the same stress. 2. The ratio of the Young modulus of P to that of Q is roughly two. 3. For strain less than $0.1$, R obeys Hooke’s law.

Stress and strain

An object with a weight of $10\,\text{kN}$ is supported equally by four solid steel rods. Each rod has a length of $2.0\,\text{m}$ and a cross-sectional area of $250\,\text{mm}^2$. As a result of the object’s weight, the rods shorten by $0.10\,\text{mm}$. The rods obey Hooke’s law. Calculate the Young modulus of steel.

Stress and strain

The graph illustrates the way the length of a spring changes as the force on it is increased. The regions P and Q are marked. Which region represents the work done in stretching the spring?

Energy conservation

A beam of vertically polarised light with amplitude $A$ strikes a polarising filter at normal incidence. The filter’s transmission axis makes an angle of $50^{\circ}$ with the vertical. What is the amplitude of the light in the beam after it has passed through the filter?

Polarisation

A progressive longitudinal sound wave travels through air. The diagram shows the positions of the air particles along part of the wave at one instant. Point Q is at a distance $x$ from point P. Which graph shows how the displacement of the air particles varies with distance from P along the wave?

Transverse and longitudinal waves

A free-space electromagnetic wave has a frequency of $3.0 \times 10^{16}\,\text{Hz}$. Which row states the principal region of this wave and gives an example of an electromagnetic wave with a lower frequency?

Electromagnetic spectrum

A source of sound sends out waves with a fixed frequency. Relative to a stationary observer, the source travels in a straight line at a constant speed. Which source velocity produces the lowest observed frequency?

Doppler effect for sound waves

What term could be used to describe the time-base of a cathode-ray oscilloscope (CRO)?

Practical circuits

What occurs when two waves superpose at one point?

Interference

An electromagnetic wave undergoes diffraction when it goes through a single slit. The slit width is greater than the wave’s wavelength. Which alteration will reduce the amount of diffraction of the wave?

Diffraction

A solid bar has a square cross-section. Its length is recorded as $50.0 \pm 0.2\,\text{cm}$ and its width is recorded as $2.00 \pm 0.01\,\text{cm}$. These measurements are then used to find the volume of the bar. Calculate the percentage uncertainty in the volume found.

Errors and uncertainties

The diagram illustrates visible light falling normally on a diffraction grating. An intensity pattern with maxima is formed on the screen. A line joining the centre of the fourth order intensity maximum to the centre of the diffraction grating makes an angle of $53^\circ$ with the centre line. The grating has a line spacing of $2.7 \times 10^{-6}\,\text{m}$. What is the wavelength of the incident light?

The diffraction grating

A glass tube placed horizontally is sealed at one end, and a layer of dust has been spread along the inside bottom surface. A loudspeaker is positioned close to the open end of the tube and sends out sound. The sound frequency is adjusted, and at one particular frequency a stationary wave is produced in the tube, causing the dust to collect into small heaps. The separation between four heaps of dust is $30\,\text{cm}$. The speed of sound in the air inside the tube is $330\,\text{m s}^{-1}$. What frequency does the loudspeaker emit?

Stationary waves

A resistor carries a current for a brief time interval. Which statement about the total charge that passes through the resistor is correct?

Electric current

The potential difference $V$ across a filament lamp is increased slowly from zero until it reaches its normal operating value. Which graph shows how the current $I$ in the lamp changes with $V$?

Resistance and resistivity

A wire of length $0.35\,\text{m}$ carries an electric current of $12\,\text{A}$. The mean drift speed of the free electrons (charge carriers) in the wire is $5.0 \times 10^{-4}\,\text{m s}^{-1}$. Determine how many free electrons are in the wire?

Electric current

A cell with negligible internal resistance is connected to three resistors. In which circuit is the total resistance $100\,\Omega$?

Resistance and resistivity

Each of Kirchhoff’s laws expresses a conservation principle for a physical quantity. Which quantity is conserved by each law?

Kirchhoff's laws

A cell with electromotive force (e.m.f.) $1.50\,\text{V}$ supplies a current of $0.26\,\text{A}$ to a resistor of resistance $5.0\,\Omega$ placed across its terminals. What is the internal resistance of the cell?

Potential difference and power

Which option is not one of the quark flavours?

Fundamental particles

What is the number of down quarks in a nucleus of hydrogen-3, $^{3}_{1}\text{H}$?

Atoms, nuclei and radiation

The graph indicates how the acceleration of an object moving along a straight line changes with time. At the start, the object is stationary. Which graph shows how the velocity of the object varies with time over the same time interval?

Equations of motion

An isotope of boron decays to beryllium through $\beta^+$ emission. Which particle is emitted along with the $\beta^+$ particle?

Atoms, nuclei and radiation

A stone is released from rest and falls vertically downward. Air resistance is negligible. Determine the speed of the stone after it has dropped a distance of $0.40\,\text{m}$?

Equations of motion

A ball is projected horizontally from a tall building. The ground below is level. Air resistance is negligible. Which statement about the motion of the ball is correct?

Equations of motion

A moving object collides with an object that is at rest. The collision is inelastic, and the objects continue together after impact. Assume that the two objects make up an isolated system. Which row shows the possible values of total momentum and total kinetic energy for the system before and after the collision?

Linear momentum and its conservation

The graph illustrates how quantity Y changes with quantity X for an object descending vertically at its terminal velocity towards the surface of the Earth. Which quantities could X and Y be?

Equations of motion

A ball with mass $2.0\,\text{kg}$ moves horizontally at a speed of $4.0\,\text{m s}^{-1}$. It strikes a wall and then rebounds in the opposite direction at a speed of $2.8\,\text{m s}^{-1}$. The collision lasts for $150\,\text{ms}$. What is the average force exerted on the wall?

Momentum and Newton's laws of motion

Which statement concerning physical quantities is correct?

Physical quantities

Two objects X and Y make up an isolated system. X and Y collide and then move apart. The mass of X is larger than the mass of Y. Which statement about the collision is correct?

Linear momentum and its conservation

Which row gives whether total momentum and total kinetic energy are conserved in an inelastic collision when no external forces act?

Linear momentum and its conservation

A tennis ball is projected straight upwards. It rises to its maximum height and then comes back down to the place where it was released. Air resistance is significant. At which point on the tennis ball’s journey is the resultant force on the tennis ball greatest?

Momentum and Newton's laws of motion

Which statement gives the correct description of a couple?

Turning effects of forces

A beam of uniform density has a mass of $1.4\,\text{kg}$ and is supported on a pivot at P, as shown. Its length is $0.60\,\text{m}$, and P is located $0.20\,\text{m}$ from one end. Masses of $3.0\,\text{kg}$ and $6.0\,\text{kg}$ are hung at distances of $0.35\,\text{m}$ and $0.15\,\text{m}$ from the pivot, as shown. Calculate the torque that has to be applied to the beam so that it remains in equilibrium?

Turning effects of forces

The diagrams illustrate three rigid objects P, Q and R that are acted on by different combinations of forces. Which objects are in equilibrium?

Equilibrium of forces

The diagram illustrates two immiscible liquids, P and Q, which remain in equilibrium within an open U-tube. The three distances marked $x$ are equal. Determine the ratio $\dfrac{\text{density of P}}{\text{density of Q}}$?

Density and pressure

A stone with mass $0.30\,\text{kg}$ is projected straight downward at a speed of $20\,\text{m s}^{-1}$ from a point $12\,\text{m}$ above the ground. It moves vertically until it reaches the ground. Air resistance may be ignored. What is the kinetic energy of the stone immediately before it hits the ground?

Gravitational potential energy and kinetic energy

A student may either run or walk up the stairs to reach her classroom. Which statement explains the power needed and the gravitational potential energy gained when she runs up the stairs compared with when she walks up them?

Gravitational potential energy and kinetic energy

A trolley travelling along a rail carries a hanging weight $W$. As the trolley shifts horizontally by a distance $p$, it at the same time lifts the weight upward by a height $q$. Consequently, the weight travels a distance $r$ from X to Y. It is at rest at the beginning and also at the end. What amount of work is done on the weight in this process?

Gravitational potential energy and kinetic energy

What would be a sensible estimate for the mass of a solid copper sphere with a diameter of $60\,\text{cm}$?

Density and pressure

The equation for kinetic energy $E_k$ may be obtained from the equations of motion. Four equations connected with motion are given below. 1. $W = Fs$ 2. $F = ma$ 3. $v^2 = u^2 + 2as$ 4. $P = \dfrac{W}{t}$ Which three equations are suitable for deriving the equation for $E_k$?

Equations of motion

A force–extension graph for a metal wire is shown. At which point on the graph does the metal wire cease to obey Hooke’s law?

Elastic and plastic behaviour

A wire with a uniform cross-section is formed from a metal whose Young modulus is $1.3 \times 10^{11}\,\text{Pa}$. Its length is $2.4\,\text{m}$, and its spring constant is $2.7 \times 10^{4}\,\text{N m}^{-1}$. What is the volume of the wire?

Stress and strain

A rubber cord is suspended from a fixed support. A load attached to its lower end is steadily increased from zero, and then steadily decreased back to zero. The force-extension graph for contraction lies beneath the force-extension graph for stretching. What does the shaded region between the graphs represent?

Elastic and plastic behaviour

A source of sound waves with a constant frequency is moving as shown. In which case would the stationary observer hear a sound of the lowest frequency?

Doppler effect for sound waves

Every main type of radiation in the electromagnetic spectrum has its own wavelength range. Which wavelength is correctly matched with its radiation?

Electromagnetic spectrum

A transverse water wave has frequency $15\,\text{Hz}$, wavelength $0.12\,\text{m}$ and amplitude $4.0\,\text{mm}$. $P$ is a water particle that starts at the crest of the wave, as shown. What total vertical distance does $P$ travel in a time of $0.5\,\text{s}$?

Transverse and longitudinal waves

A wave is produced on a string. A student draws a graph showing how displacement $d$ changes with time $t$ for a point on the string. The student labels two points, $X$ and $Y$, on the graph. Which wave property is shown by the horizontal-axis distance between $X$ and $Y$?

Progressive waves

A stationary wave is produced in a stretched string. Which distance is equal to the wavelength of the wave?

Stationary waves

A source of coherent light falls on two slits, $P$ and $Q$, separated by $80\,\text{mm}$. The light has a single frequency of $1.5 \times 10^{12}\,\text{Hz}$. Light emerging from the slits is received on a screen that is $4.0\,\text{m}$ from the slits. The screen is parallel to the line joining the slits. An intensity sensor is positioned on the screen at the centre of the interference pattern so that the reading is at a maximum. The intensity sensor is then moved along the screen. The sensor passes through two intensity minima, two intensity maxima and comes to rest at the centre of the third intensity minimum. Which distance does the sensor move through?

Interference

A star’s power output $P$ may be represented by $P = \sigma A T^4$, where $\sigma$ is a constant, $A$ denotes the star’s surface area, and $T$ is the star’s surface temperature. Which SI base units does $\sigma$ have?

SI units

Surface water waves are generated in a ripple tank by a vibrating bar. The wavelength of the waves is $5.0\,\text{cm}$, and they move through a gap with width $20\,\text{cm}$. Which change would cause more diffraction to be observed?

Diffraction

What does electric current mean?

Electric current

A wire with diameter $d$ forms part of an electric circuit. A current $I$ flows through the wire, and the charge carriers have a mean drift speed $v$. The wire is then changed to another wire made from the same material, but with diameter $0.5d$. The current is adjusted so that the charge carriers in the new wire have a mean drift speed $3v$. Determine the current in the new wire.

Electric current

A fixed resistor and a diode are linked together in series. The potential difference $V$ across the pair is changed, and the resulting current $I$ is then measured. Which graph might show how $I$ varies with $V$?

Practical circuits

The potential difference (p.d.) across a fixed resistor is $V$. The resistor dissipates power of $5.0\,\text{W}$. The p.d. across the resistor then takes a different value. At this new p.d., the energy transferred to the resistor during $2.25\,\text{s}$ is $45.0\,\text{J}$. Determine the new p.d. across the resistor?

Potential difference and power

The diagram illustrates a section of a circuit that uses a potentiometer wire to measure a potential difference (p.d.) in an external circuit. The potentiometer wire $XZ$ has length $L_1$. It is connected to a cell with known electromotive force (e.m.f.) $E$ and negligible internal resistance. The terminals $P$ and $Q$ are linked to the external p.d. that is to be measured. The length of the potentiometer wire from $X$ to $Y$ is $L_2$. The ratio of the lengths $L_1$ and $L_2$ is used to find the p.d. between $P$ and $Q$ in terms of $E$. What condition has to be satisfied to determine this p.d.?

Practical circuits

The diagram illustrates a circuit. Which statement about the circuit is incorrect?

Practical circuits

A circuit includes a battery with electromotive force $E$ and internal resistance $r$, linked to two resistors, each having resistance $2.5\,\Omega$. The resistors are arranged in parallel, as shown. The current through one of the resistors is $0.80\,\text{A}$. Which expression, with $E$ measured in volts and $r$ measured in ohms, determines the internal resistance $r$?

Potential difference and power

What is the rest mass of a beta particle?

Atoms, nuclei and radiation

What are the names of the group (class) of particles that includes mesons, and the group (class) of particles that includes baryons?

Fundamental particles

From the top of a building, a boy throws a stone with a horizontal velocity of $10\,\text{m s}^{-1}$. The building is $8.0\,\text{m}$ high. The stone follows a curved path before striking the horizontal ground, as shown. Air resistance is negligible. Calculate how long the stone takes to reach the ground.

Equations of motion

A magnesium nucleus $^{23}_{12}\text{Mg}$ undergoes decay, releasing two particles. The daughter nucleus is sodium $^{23}_{11}\text{Na}$. Which two particles are released?

Atoms, nuclei and radiation

Four cuboids with the same lengths, breadths and heights are placed in water. The cuboids are kept at an equal depth and in the same orientations by vertical rods, as illustrated. Water has density $\rho$. Cuboid W is made from a material of density $4\rho$. Cuboid X is made from a material of density $2\rho$. Cuboid Y is made from a material of density $\rho$. Cuboid Z is made from a material of density $0.5\rho$. Which statement is correct?

Density and pressure

In which example is equilibrium impossible for the underlined object?

Equilibrium of forces

Two identical balls are launched vertically upwards from ground level with the same initial velocity. Ball X moves in a vacuum, whereas ball Y moves in air. Which statement about the motion of the balls is correct?

Non-uniform motion

The graph illustrates how the velocity of a stone changes with time as it drops from a bridge into a lake and then sinks to the lake bed. What can be deduced about the stone's motion?

Equations of motion

The graph illustrates how the momentum $p$ of a car varies with time $t$. What is the resultant force acting on the car when $t = 10\,\text{s}$?

Momentum and Newton's laws of motion