Question

A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a levelled road. If the value of g be 10 m s⁻², what will be the work done by the girl against the gravitational force?

Answer 1

Given Data:

Mass of the school bag (m) = 3 kg

Horizontal distance moved (s) = 200 m

Acceleration due to gravity (g) = 10 m s⁻²

The force exerted by the girl to hold the bag acts in the vertically upward direction, while her displacement is in the horizontal direction along the leveled road. Therefore, the angle (θ) between the force and the displacement is 90°.

Using the work formula:

W = F × s × cos θ

W = F × 200 × cos 90°

Since cos 90° = 0:

W = F × 200 × 0

W = 0 J

The work done by the girl against the gravitational force is 0 Joules.