Question

A man of mass 50 kg climbs up a ladder of height 15 m. Calculate:

1. the work done by the man,
2. the increase in his potential energy. (g = 9.8 m s^-2)

Answer 1

Mass of man = 50 kg

Height of ladder, h₂ = 15 m

(i) Work done by man = mgh₂

= 50 × 9.8 × 15 = 7350 J

(ii) increase in his potential energy:

Height, h₂ = 15 m

Reference point is ground, h₁ = 0m

Gravitational potential energy = Mg (h₂ - h₁)

= 50 × 9.8 × (15 - 0)

= 50 × 9.8 × 15

= 7350 J