Question

A 1000kg car moving at 15m/s to the right collided head-on with another 1500 kg car who was coming in the opposite direction at a speed of 20m/s. After collision the two cars interlocked to each other, and the wreckage dragged with a new speed. What is the lost of kinetic energy during the collision ?

A 1000 kg moving at 15 m/s to the right collided head-on with another 1500 kg car who was coming in the opposite direction at a speed of 20m/s . After collision the two cars interlocked to each other, and the wreckage dragged with a new speed. What is the lost of kinetic energy during the collision? O A. 400,000) O B. 367,500) O C.254,235) OD. 125,500)

Answer 1

Using the momentum conservation equation,

$$$\begin{array}{l}{m_1}{v_1} + {m_2}{v_2} = \left( {{m_1} + {m_2}} \right)v\\\left( {1000kg} \right)\left( {15m/s} \right) + \left( {1500kg} \right)\left( { - 20m/s} \right) = \left( {1000kg + 1500kg} \right)v\\\left| v \right| = 6m/s\end{array}$$$

The lost energy is:

E = Ei – Ef AE = ({mpuſ + {mauk) (mı + m2) v2 AE = (į (1000kg) (15m/s) +į (1500kg) (20m/s)?) – į (1000kg + 1500kg) (6m/s)? AE = 367500J

Therefore, option B is correct.