Question

a girl of mass of 40 kg jumps with horizontal velocity of 5 m/s on to a stationary cart with friction less wheels. The mass of the cart is 3 kg. What is her velocity as the cart start moving? Assume that there is no external force working in the horizontal direction​

Answer 1

Explanation:

Let v be the velocity of the girl on the cart as the cart starts moving.

The total momenta of the girl and cart before the interaction = (50 x 5 m s-1) + (4 x 0 m s-1)

= 250 kg m s-1

The total momenta after the interaction = (50 + 4) kg x v m s-1

= 54 v kg m s-1

According to the law of conservation of momentum,

Total momentum before the interaction = Total momentum after the interaction