JEE Main & Advanced Physics Rotational Motion Question Bank Mock Test - Centre of Mass, Conservation of Linear Momentum and Collisions

  • question_answer
    A block of mass \[m\] starts from rest and slides down a frictionless semi-circular track from a height h as shown. When it reaches the lowest point of the track, it collides with a stationary piece of putty. also having mass m. If the block and the putty stick together and continue to slide, the maximum height that the block-putty system could reach is

    A)  \[h\]/4              

    B)  \[h\]/2

    C)  \[h\]                

    D)  independent of \[h\]

    Correct Answer: B

    Solution :

    [b] \[{{v}_{0}}=\sqrt{2gh}\] before collision. Apply conservation principle of momentum, \[m{{v}_{0}}=(m+m)u\] \[\therefore u=\frac{{{v}_{0}}}{2}\] Applying conservation principle of momentum, \[\frac{1}{2}(2m){{u}^{2}}=2mgh'\] \[\therefore h'=\frac{{{u}^{2}}}{2g}\Rightarrow h'\Rightarrow =\frac{{{v}^{2}}_{0}}{4g}\] \[h'=\frac{2gh}{4g}\Rightarrow h'=\frac{h}{2}\]


You need to login to perform this action.
You will be redirected in 3 sec spinner