Two identical balls `A and B` each of mass `0.1 kg` are attached to two identical mass less is springs. The spring-mass system is constrained to move inside a right smooth pipe bent in the form of a circle as shown in figure . The pipe is fixed in a horizontal plane. The center of the balls can move in a circle of radius `0.06 m`. Each spring has a natural length of `0.06 pi m` and force constant `0.1 N//m`. Initially, both the balls are displaced by an angle `theta = pi//6` radians with respect to diameter PQ of the circle and released from rest.
a. Calculate the frequency of oscillation of the ball B.
b. What is the total energy of the system ?
c. Find the speed of the ball A when A and B are at the two ends of the diameter PQ.

Answer

A, B, D

Explanation

(i) This system can be reduced to

Where `mu = (m_(1)m_(2))/(m_(1) + m_(2)) = ((0.1)(0.1))/(0.1+0.1) = 0.05 kg`
and `k_(eq) = k_(1) + k_(2) = 0.1 + 0.1 = 0.2 Nm^(-1)`
`rArr f = (1)/(2pi) sqrt((k_(eq.))/(mu)) = 1/2pi sqrt((0.2)/(0.05)) = 1/(pi) Hz`
(ii) Compression in one spring is equal to extension in other spring
`= 2Rtheta = 2(0.6)(pi/6) = (pi)/(50)m`
`= 2Rtheta = 2(0.06)(pi)/(6) = (pi)/(50)m`
Total energy of the system
`e = 1/2k_(1)(2Rtheta)^(2) +1/2k_(2)(2Rtheta)^(2)`
`= k(2Rtheta)^(2) = (0.1)(pi/5)^(2) = 4pi xx 10^(-5)J`
(iii) From mechanical energy conservation
`1/2m_(1)v_(1^(2)) + (1)/(2)m_(2)v^(2^(2)) = E`
`rArr 0.1v^(2) = 4pi^(2) xx 10^(-5) rArr v = 2pi xx 10^(-2)ms^(-1)`