Question

a girl of mass 30 kg jumps on a cart of mass 5 kg with a velocity of 10 metre per second find the velocity with which she and cart start moving after she jumps on it

Answer 1

answer is 50/35
apply momentum conservation law

Answer 2

Explanation:

It is given that,

Mass of the girl, m₁ = 30 kg

Mass of the cart, m₂ = 5 kg

Speed of the girl, u₁ = 10 m/s

Speed of the cart, u₂ = 0

Let V is the  velocity with which she and cart start moving after she jumps on it. It can be calculated using the conservation of momentum as :

$m_1u_1+m_2u_2=(m_1+m_2)V$

$V=\dfrac{m_1u_1+m_2u_2}{(m_1+m_2)}$

$V=\dfrac{30\times 10+0}{35}$

V = 8.57 m/s

So, the final speed of the cart and the girl is 8.57 m/s. Hence, this is the required solution.