Question

A 1300 kg car moving at 20 m/s and a 900 kg car moving at 15 m/s in precisely opposite directions participate in a head-on crash. This event was a perfectly inelastic collision. What do you do first?

(A) Find the total momentum of the system before the collision.
(B) Find the final velocity of the system after the collision.
(C) Find the change in kinetic energy of the system during the collision.
(D) Find the forces that acted on the cars during the collision.

Answer 1

To deal with the inelastic collision question, first find the total momentum of the system before the collision, using each car's mass and velocity, with direction considered by assigning positive or negative signs to the velocities.

Step-by-step explanation:

When dealing with a head-on collision where two vehicles are involved in a perfectly inelastic collision, the first step is to find the total momentum of the system before the collision (A). This is because, in an inelastic collision, the total momentum of the system is conserved even though kinetic energy is not conserved. To calculate the total momentum, you take the mass of each car and multiply it by its velocity. Remember to account for the directions by assigning positive or negative values according to a chosen coordinate system. For the given question, you would use the equation p = mv for each car and then add these momenta together, keeping in mind that they are moving in opposite directions. The mass and velocity of the first car would be 1300 kg and 20 m/s, and for the second car, 900 kg and 15 m/s. Because they are moving toward each other, one of these velocities would be negative in your calculation.