Question

A man mass 62 kg is standing on stationary boat if mass 238 kg the nan carry so here mass 0.5 throws it horizontally with u = 12 m s find the velocity with which boat move

Answer 1

initially, man, boat and sphere all are in rest. so, initial linear momentum of system = 0

now, the man throws a sphere of mass 0.5kg with speed 12m/s in horizontal direction.

so, linear momentum of sphere = mv = 0.5kg × 12m/s = 6 Kgm/s

Because, no external force is acting on system so, linear momentum will be conserved.

i.e., initial linear momentum = final linear momentum

⇒0 = 6 + linear momentum of man + linear momentum of boat.

if we assume man doesn't move with respect to boat.

then, velocity of boat = velocity of man = v' (let)

now, 0 = 6 + 62 × v' + 238 × v'

⇒0 = -6 + 300v'

⇒v' = -6/300 = -0.02 m/s

hence, velocity of boat is -2 × 10^-5 m/s