NTA Abhyas JEE Main2020PhysicsLaws of MotionPractice
A ball is held at rest at position A by two light strings. The horizontal string is cut and the ball starts swinging like a pendulum. Point B is the farthest to the right the ball goes as it swings back and forth. What is the ratio of the tension in the supporting string in position B to its value at A before the horizontal string was cut?
Options
- Asin 2 β
- Bcos 2 β
- Ctan 2 β
- Dcos β
Correct answer
B. cos 2 β
Step-by-step solution
At A: T ′ cos β = m g T ′ = m g cos β At: B T ′ ′ - m g cos β = m v 2 1 at B ; v = 0 T ′ ′ = m g cos β T ′ ′ T ′ = m g cos β m g / cos β T e n s i o n a t B T e n s i o n a t A = T ′ ′ T ′ = c o s 2 β