A girl having mass of 35kg sits on a trolley of mass 5kg. The trolley is given an initial velocity of 4m/s by applying a force. The trolley comes to rest after travelling a distance of 16m.
(a) How much work is done on the trolley?
(b) How much work is done by the girl?
A girl having mass of 35kg sits on a trolley of mass 5kg. The trolley is given an initial velocity of 4m/s by applying a force. The trolley comes to rest after travelling a distance of 16m.
(a) How much work is done on the trolley?
(b) How much work is done by the girl?
(a) Given,
Mass of girl = 35 kg
Mass of trolley = 5 kg
Total mass, m = (35 + 5) = 40 kg
Initial velocity, u = 4 m/s
Final velocity, v = 0
Distance travelled, s = 16 m
By equation,
v²= u² + 2as
0 = (4)² + 2a (16)
32a = –16
a = –0.5 m/s²
Force exerted on the trolley,
F = ma = 40 × 0.5 = 20 N
Work done on trolley W = FS = 20 N x 16 m = 320 J
(b) Work done by the girl is zero as she is stationary with respect to the cart i.e.; her displacement with respect to the cart is zero.
(a) Given,
Mass of girl = 35 kg
Mass of trolley = 5 kg
Total mass, m = (35 + 5) = 40 kg
Initial velocity, u = 4 m/s
Final velocity, v = 0
Distance travelled, s = 16 m
By equation,
v²= u² + 2as
0 = (4)² + 2a (16)
32a = –16
a = –0.5 m/s²
Force exerted on the trolley,
F = ma = 40 × 0.5 = 20 N
Work done on trolley W = FS = 20 N x 16 m = 320 J
(b) Work done by the girl is zero as she is stationary with respect to the cart i.e.; her displacement with respect to the cart is zero.
