A man of 60 kg is running on the road and suddenly jumps into a stationary trolly car of mass 120 kg. Then, the trolly car starts moving with velocity 2ms–1. The velocity of the running man was _____ ms–1, when he jumps into the car.
Correct Answer: 6
Solution and Explanation
The correct answer is 6
By taking the system as man and trolley and using conservation of linear momentum :
\(v_m = \frac{(120+60)v_T}{60} \)
\(= \frac{180 × 2}{60}\)
= 6 m/s
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Concepts Used:
Momentum
It can be defined as "mass in motion." All objects have mass; so if an object is moving, then it is called as momentum.
the momentum of an object is the product of mass of the object and the velocity of the object.
Momentum = mass • velocity
The above equation can be rewritten as
p = m • v
where m is the mass and v is the velocity.
Momentum is a vector quantity and the direction of the of the vector is the same as the direction that an object.