A boy of 50kg mass is running with a velocity of 2 m/s. He jumped into a stationary cart of 2kg while running. Find the velocity of cart after the boy jumped into it. (in m/s)
Given,
Mass (m1) of boy = 50kg
Initial velocity (u1) of boy = 2 m/s
Mass (m2) of cart = 2kg
Initial velocity (u2) of cart = 0
Final velocity of cart (v2) =?
Since, boy jumped into the cart, the final velocity (v1) of the boy will be equal to that of the cart.
Therefore, v1 = v2
We know that,
m1u1 + m2u2 = m1v1 + m2v2
⇒ (50kg x 2 m/s) + (2kg x 0) = (50kg x v1) + (2kg x v2)
since, v1 = v2
100kg.m/s = (50kg x v2 ) + (2kg x v2)
100kg.m/s = 52kg x v2
v2 = 100kg.m/s52kg = 1.92 m/s
Therefore, velocity of cart after jumping of boy over it is equal to 1.92 m/s. Since, velocity has positive sign, thus, cart will go in the same direction of boy.