Question

A simple pendulum of length l and mass m is initially at its lowest position. It is given the minimum horizontal speed necessary to move in a circular path about the point of suspension. The tension in the string at the lowest position of the bob is-

• A. 3 mg
• B. 4 mg
• C. 5 mg
• D. 6 mg

Answer 1

Answer: (D)

6 mg

Answer 2

To complete the circle v_min = $\sqrt{5g\mathcal{l}}$

T – mg = $\frac{mv^{2}}{\mathcal{l}}$; T – mg = 5 mg

T = 6mg