Q.

A particle is moving on a circular path of 10 m radius. At any instant of time, its speed is 5 m s-1 and the speed is increasing at a rate of 2 m s-2. The magnitude of net acceleration at this instant is

1 5 m s-2  
2 2 m s-2  
3 3.2 m s-2  
4 4.3 m s-2  

Ans.

(3)

Here, r=10 m, v=5 m s-1, at=2 m s-2

ar=v2r=5×510=2.5 m s-2

The net acceleration is

a=ar2+at2=(2.5)2+22=10.25=3.2 m s-2