A girl of mass $30 k g$ jumps on a cart of mass $5 k g$ with a velocity of $10 m / s$ . Find the velocity with which she and cart moving after she jumps on it.

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Solution

Mass of the girl $(m_{1}) = 30 k g$
Initial velocity of the girl $(u_{1}) = 10 m / s$
Mass of the cart $(m_{2}) = 5 k g$
Initial velocity of the cart $(u_{2}) = 0$
Final velocity of the girl and cart $= v$
Initial momentum of the girl and cart before she jumps on the cart $= m_{1} u_{1} + m_{2} u_{2}$
$= 30 \times 10 + 0................ (i)$
Final momentum of the girl and cart before she jumps on the cart $= (30 + 5) \times v . . . . . . . . . (i i)$
By law of conservation of momentum
Eq (i)=Eq(ii)
$(30 \times 10) = (30 + 5) \times v$
$v = \frac{30 \times 10}{(30 + 5)}$
$v = 8.57 m / s$

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A girl of mass 30kg jumps on a cart of mass 5kg with a velocity of 10m/s. Find the velocity with which she and cart moving after she jumps on it.

A girl of mass $30 k g$ jumps on a cart of mass $5 k g$ with a velocity of $10 m / s$ . Find the velocity with which she and cart moving after she jumps on it.