The damage would depend on composition where it hit, its velocity, and its mass.
If you consider it car-sized, and use 1600 Kg for the mass [[around 3500 pds.) and a velocity of around 20,000 meters per second, it would hit at around 320 BILLION joules, or roughly 320,000 sticks of dynamite [[less than a tenth of amegaton), if it was able to make it through to the surface without fragmenting or exploding higher in the atmosphere, it would do significant, local damage, but not Hiroshima-esque.

Remember the Chelyabinsk event was a rock around 66 feet around. The Tunguska event was caused by a rock of around 330 feet.