Question

Is the total energy of the car at the top of its track exactly equal to the total energy at the bottom of its track? If not, where does the lost energy go?

Answer 1

No, The total energy of the car at the top of its track is not equal to the total energy at the bottom of the surface.

At top

Potential energy=mgh (m= mass of the car, g= gravitational acceleration, h= height from the bottom)

Kinetic energy = 1/2 mv² (m= mass of the car, v= velocity of the car at top)

Total energy = mgh+ 1/2mv²

At bottom

Potential Energy = 0

Kinetic energy = 1/2mu² (u= velocity of car at bottom)

Due to the presence of friction some mechanical energy will be wasted (thats mean converted into heat energy, sound energy etc).That's why total energy at top and bottom are not exactly equal.