Question

A girl having mass of 35 kg sits on a trolley of mass 5 kg. The trolley is given an initial velocity of 45 ms- by applying a force. The trolley comes to rest after traversing a distance of 16 m.
(a) How much work is done on the trolley?
(b) How much work is done by the girl? (g=10ms-²)​

Answer 1

mass of girl m=35kg

mass of trolley=5kg

total mass=40kg

initial velocity of trolley u=4ms

−1

final velocity of trolley v=0ms

−1

distance s=16m

we know,

v

2

−u

2

=2as

a=

2s

v

2

−u

2

=−

2×16

16

a=−

2

1

ms

−2

Force=ma=40×(−0.5)

=-20N

work is done on the trolley=20N×16m=320 J.

work was done by the girl =0 J.