Question

Adjacent diagram shows a body of mass 5 kg pulled up an inclined plane by a force of 30 N.

1. Calculate force of gravity acting on body.  (Take g = 10 ms⁻²)
2. Work done by the force in pulling body along the inclined plane.
3. Work done against the force of gravity.

Answer 1

(a) Force of gravity (weight) = mg

= 5 × 10

= 50 N

(b) Work done by the pulling force = F × s

= 30 × 5

= 150 J

(c) Work done against gravity = mgh

= 5 × 10 × 3

= 150 J