Question

A small body tied to a string is revolved in a vertical circle of radius 0.8m such that its speed at the top of the circle is 4 m/s.Find the maximum speed of the body during the motion.​

Answer 1

Answer:

6.88 m/s

Explanation: Maximum velocity is at the point where PE = 0, at the bottom.

  Let the mass of the body be m.

At the highest point:  

height = 2r = 2(0.8) = 1.6  ;  u(velocity) = 4 m/s

 Total energy = KE + PE

            = mgh + 1/2 mu²

            = m(9.8*1.6 + 1/2 (4)² )    

            = (23.68)m

At the lowest point:

Total energy = mg(0) + 1/2 mv²

          (23.68)m = 0 + 1/2 m v²

           23.68 = 1/2 v²

           47.36 = v²

           6.88 m/s = v

Since velocity at the bottom is maximum, maximum velocity is 6.88 m/s