Question

A particle is moving along a circular path of radius 5m with a uniform speed 5m per second. What will be the average acceleration when the particle completes half revolution?

Answer 1

As the average acceleration is change in velocity over the time taken,

In this case when the half revoultion is over the direction in the speed changes by 180 degrees, so the change in velocity = 5- (-5) = 10 m/s.

The time taken to cover this distance = (π×r)/5=(5π)/5=π (as the distance travelled is semicircle).
So, average acceleration = 10/π m/s.