A ball attached to a string moves in a horizontal circle of radius 1 m.It makes one revolution in 4 seconds.The magnitude of its acceleration is A)2.5 m/s². B)3.9 m/s². C)6.4 m/s². D)9.8 m/s². E)12.4 m/s².

Question

Quizplus · Accepted Answer

The correct answer is A because the magnitude of the acceleration of the ball is given by a = v^2/r, where v is the speed of the ball and r is the radius of the circle. In this case, v = 2πr/T = 2π(1 m)/(4 s) = π/2 m/s and r = 1 m, so a = (π/2 m/s)^2/1 m = 2.5 m/s^2.

A Ball Attached to a String Moves in a Horizontal