Question

a child of mass 35kg is sitting on a trolley of mass 5kg.the trolley is given a push by applyinga force so that it begins to move with a speed of 4 m/s.the trollye comes to rest after covering a distance of 16m find
1) work done on the trolley
2) work done by the trolley before coming to rest

Answer 1

Total mass of system=35+5=40kg
initial velocity(u)=4m/s
distance covered(s)=16m
final velocity(v)=0m/s
work done by trolley=v²-u²=2as
16=2a×16
a=1/2
f=m×a
f=40×1/2
=20N
w=f×s=20×16
=320J

Answer 2

work done by trolley=v²-u²=2as
16=2a×16
a=1/2
f=m×a
f=40×1/2
=20N
w=f×s=20×16
=320J