Q.25 Calculate the work done by a car against gravity in moving along a straight horizontal road. The mass of the car is 400 kg and the distance. moved is 2 m.

Hint: Work done by the force is zero if the angle between force and displacement is 90°.

Step 1: Find work done by the car against gravity.

The force of gravity acts on the car vertically downward while the car is moving along a horizontal road, i.e., the angle between them is 90°

 Work done by the car against gravity

W = Fs cos 90° = 0                   cos 90° = 0