If radar use EM energy wave why isnt aborbed in the metal of the Car?when energy is absorbed ,no reflection?

Answer 1

do not forget that EM energy is a lot of things... Including normal visible light...
We see the reflection of EM waves bouncing of a car all the time.

The same is true for other EM waves... many of them will be partialy or fully reflected by metalic objects.

(unless you are using stealth materals, those were designed to absorb waves used in radar. )

Answer 2

Whether an EM wave is absorbed or reflected depends on the energy of that wave and the angle that the wave hits the object. By knowing the energy of the wave, we also know its wavelength. A few things can happen when the wave hits an object. It can be absorbed, partially reflected, totally reflected, or scattered.

The rader used to locate planes is designed to use frequencies that will reflect off of planes, missiles, and other metallic objects. The same thing is true with a law enforcement speed radar. Stealth works by using special paints to absorb radar as well as unusual curved and angled surfaces to scatter it. By using this combination, as well as a few technologies our government keeps secret, very little radar energy is sent back to the source.