question_answer

A truck weighing 2500 kg and moving with a velocity \[\text{28 m}{{\text{s}}^{\text{-1}}}\] collides with a stationary car weighing 300 kg. The truck and the car move together after the impact. Then find their common velocity.

Answer:

Before collision : Momentum of truck   \[=2500\times 28=70,000\,\,N\,s\] Momentum of car = 0 Total Momentum of the system = 70,000 Ns After collision: Let v = velocity of the system Total mass of the system \[=2500+300=2800\,\,kg\] Total momentum of the system = 2800 v Ns According to the law of conservation of momentum \[2800\,\,\,v=70,000\,\,\,or\,\,\,v=\frac{70000}{2800}\,\,or\,\,\,V=25\,m{{s}^{-1}}\]