Question

A girl of mass 40 kg jumps with a horizontal velocity of 5 m/s onto a cart of mass

10kg with friction less wheels, which is already moving with a horizontal velocity 1 m/s

in the opposite direction of motion of the girl. What will be the velocity of the girl, when

the cart moves along with her. (Assume that there is no external unbalanced force

working in the horizontal direction)​

Answer 1

Answer:

4.2 m/s

Explanation:

law of conservation of momentum.

mass of girl(m1) = 40 kg

initial velocity of girl(u1) = 5m/s

mass of cart(m2) = 10 kg

initial vel. of cart(u2) = 1m/s

final velocity of combined system(v) = ?

see, it is a combined system because the girl came on the cart so their velocity would be same.

m1u1 +m2u2 = m1v +m2v

40*5 + 10*1 = (m1+m2)v                  #took v as common

200 + 10 = (40+10)v

210 = 50v

v = 21/5

   = 4.2 m/s

hope it helps!