The total kinetic energy of two cars is measured before and after they crash into each other. The total kinetic energy of the two cars after the crash is less than the total kinetic energy before the crash. Which of the following best explains the loss of kinetic energy

A. The car with more mass gave up its kinetic energy to the car with less mass.
B. Some of the cars' kinetic energy was converted to sound and heat energy.
C. Both of the cars were being pulled downward by the force of gravity.
D. Energy in a system is always lost.

Option B, Some of the cars' kinetic energy was converted to sound and heat energy.

Explanation:

In an elastic collision, no energy is lost during and after collision. Thus, it can be said that in an elastic collision both momentum and kinetic energy remains conserved.  

While in non-elastic collision, kinetic energy of the system is lost. However, the momentum of the system is conserved. Generally, during and after collision some of the kinetic energy is lost as thermal energy, sound energy etc.  

Hence, option B is correct

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.

i don't understand. explain it clearly