Physics 9702 · AS & A Level · Gravitational potential energy and kinetic energy

Gravitational potential energy and kinetic energy — practice question

(a)[1]

State the meaning of kinetic energy.

(b(i))[2]

A cannon launches a shell vertically upward. It leaves the cannon at a speed of $80\,\text{m s}^{-1}$ and has a kinetic energy of $480\,\text{J}$. The shell then rises to a maximum height of $210\,\text{m}$. Air resistance is significant. Show that the mass of the shell is $0.15\,\text{kg}$.

(b(ii).1)[2]

For the shell's journey from the cannon to its highest point, calculate the gain in gravitational potential energy.

(b(ii).2)[1]

For the shell's journey from the cannon to its highest point, calculate the work done against air resistance.

(b(iii))[2]

Determine the average force due to air resistance on the shell as it travels from the cannon to its maximum height.

(b(iv))[2]

The shell leaves the cannon at time $t = 0$ and reaches its maximum height at time $t = T$. On Fig. 2.1, sketch how the velocity $v$ of the shell changes with time $t$ from time $t = 0$ to time $t = T$. You do not need numerical values for $v$ or $t$.

(b(v))[2]

The force due to air resistance is a vector quantity. Compare the force due to air resistance on the shell during its rise with the force due to air resistance during its fall.

(iv)[2]

The shell leaves the cannon at time $t = 0$ and reaches its maximum height at time $t = T$. On Fig. 2.1, sketch how the velocity $v$ of the shell changes with time $t$ from time $t = 0$ to time $t = T$. You do not need numerical values for $v$ or $t$.

(v)[2]

The force due to air resistance is a vector quantity. Compare the force due to air resistance on the shell during its rise with the force due to air resistance during its fall.

Worked solution & mark scheme

This 16-mark question has a full step-by-step worked solution and mark scheme. One marking point: energy (of a mass/body/object) resulting from motion/speed/velocity

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