KVPY2018PhysicsLaws of Motion
An arrangement of spring, strings, pulley and masses is shown in the figure below. The pulley and the strings are massless and M > m . The spring is light with spring constant k . If the string connecting m to the ground is detached, then immediately after detachment
Options
- Athe magnitude of the acceleration of m is zero and that of M is g
- Bthe magnitude of the acceleration of m is M - m g / m and that of M is zero
- Cthe accelerations of both masses are same
- Dthe elongation in the spring is M - m g / k
Correct answer
B. the magnitude of the acceleration of m is M - m g / m and that of M is zero
Step-by-step solution
At t = 0 , T = m g When string is cut, mass M remains static and spring snaps. For mass m at the instant string is cut, forces on m are Acceleration of m is upwards as spring snaps, a m = F net m = M g - m g m = M - m m g