Question

A particle of mass m is moving in a horizontal circle of radius R with uniform speed v.
When it moves from one point to a diametrically opposite point,its
A)K.E changes by mv^2/4
B)P changes by 2mv
C)P does'nt change
D)K.E changes by mv^2.​

Answer 1

Answer:

The answer is option momentum changes by 2mv. (B)

Explanation:

This is because, in case of circular motion, the velocities of the body at a point and the point just diametrically opposite to it is equal but opposite. So, at point A, Velocity of the body is v.

On the opposite point,  Velocity is – v.  

Momentum at initial point $=m * v$

Momentum at diametrically opposite point $=m \times(-v)$

So change in momentum $=m v-(-m v)$

$=m v+m v=2 m v$

This is a basic problem of conservation of momentum. Based on basic principles physics, this math is done.

Answer 2

Answer: (b) momentum changes by 2mv

Hope this will help you

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