Question

55.
Q 55. A boy of mass 50 kg running at 5 m/s jumps on to a 20 kg trolly travelling in the same direction at 1.5 m/s .
What is their common velocity ?

Answer 1

Dear Student ,
Here in this case applying the conservation of momentum we get ,
$$\begin{gathered} Initialmomentum=FinalMomentum \\ \Rightarrow \left(50\times 5\right)+\left(20\times 1·5\right)=\left(50+20\right)\times V\left[V=finalcommonvelocity\right] \\ \Rightarrow 280=70V \\ \Rightarrow V=\frac{280}{70}=4m/s \end{gathered}$$
Regards