Explain what the term work done means.
A car is moving along a road with a constant downhill gradient, as shown in Fig. 2.1. The car’s total mass is $850\,\text{kg}$. The road makes an angle of $7.5^\circ$ to the horizontal. Calculate the component of the weight of the car down the slope.
The car in (b) is moving at a constant speed of $25\,\text{m s}^{-1}$. The driver then brakes to stop the car. The constant force resisting the motion of the car is $4600\,\text{N}$. Show that the deceleration of the car with the brakes applied is $4.1\,\text{m s}^{-2}$.
Calculate the distance the car covers from the moment the brakes are applied until it is at rest.
Calculate the decrease in the car’s kinetic energy.
Calculate the work done by a resisting force of $4600\,\text{N}$.
The quantities in (iii) part 1 and in (iii) part 2 are not equal. Explain why these two quantities are not equal.
Calculate the loss of kinetic energy of the car.
Calculate the work done by a resisting force of $4600\,\text{N}$.