Question

A car of mass 1050 kg is moving towards east with a speed of 15 ms-1. A truck is moving towards west. The mass of the truck is 6320 kg. both the vehicle collide head-on and remain locked together after the collision. Based on above information, answer the following question.

The loss in kinetic energy of the two vehicle system due to collision in above equation is

• A. 118125 J
• B. 137875 J
• C. 19750 J
• D. 98375 J

Answer 1

The correct option is B

137875 J

Given

Mass $m_1$=1050 kg

Mass $m_2$=6320 kg

Velocity $v_1=15m{s}^{-1}$

Velocity $v_2=10m{s}^{-1}$=10 m/s

Final velocity $v=0$

Loss in kinetic energy

Loss in kinetic energy=final K.E - initial K.E

=$\frac{1}{2}m{v}^2-[\frac{1}{2}{m}_1{v_1}^2+\frac{1}{2}{m}_2{v_2}^2]$

=$0-\frac{1}{2}[1050\times {15}^2+6320\times 2.5^2]$

loss in kinetic energy = $-137875J$

Therefore the loss in kinetic energy of the two-vehicle system due to collision is 137875 J

Hence option (b) is the right answer.