Question

In the above question, ifu=sqrt(gR) then (a) after rotating an angle theta , velocity of the bob becomes zero. Find the value of theta . (b) If mass of the bob is 'm' then what is the tension in the string when velocity becomes zero?

Answer 1

The angle and tension in the string when velocity is zero is:

• Given, $u=\sqrt{gR}$

• After rotating an angle Θ, velocity of the bob becomes zero.

• Height at which ball is present, h = $\frac{u^2}{2g} =\frac{gR}{2g} = \frac{R}{2}$

• But, height h= R (1 - cos Θ )

• Equating both equations, we get: R (1 - cos Θ ) = R/2

                                                               ⇒ Θ = 60°

• If mass of bob = m , tension in the string = T = mg cos Θ = mg/2
• Answers are  Θ = 60°  and T=mg/2

Answer 2

Answer:

yeah the above given answer is correct i had verified tq answerer