Question

A stone tied to the end of string 80cm long is whirled in horizontal circle with a constant speed. If the stone makes 14 revolutions in 25 sec, what is the magnitude of acceleration of the stone?

(a) 680 cm/s^2

(b) 860 cm/s^2

(c) 720 cm/s^2

(d) 990 cm/s^2

This question was addressed to me in semester exam.

My enquiry is from Motion in a Plane topic in portion Laws of Motion of Engineering Physics I

Answer 1

Correct option is (d) 990 cm/s^2

Easiest explanation: a = rω^2 = r(2πn/t)^2

a = (80×4×(22/7)^2×14^2)/14^2 = 990cm/s^2.