# Collisions in space/vacuum

Say an object in space collides with another object at 100mph. Say the same thing happens on Earth. Would the impact in space exert more force on the receiving object than on Earth because some energy on Earth would be lost to sound/shockwave being generated due to air being present?

It is not clear whether you mean speed at the impact is same on earth and in space. Assuming the speed at the time of impact is same, then the answer is no.

If the speed is at 100 mph till sometime before the impact and then the object is left on its own, then, yes, the air resistance will slow down the object before the impact and the speed of impact will be lesser.

If you meant the shock wave after the impact, then, also, the answer is no. The shock waves are created as a result of impact force. As they are consequence of the impact force, they would not reduce the force of impact. However, some energy will be lost from the two bodies post impact on earth due to sound waves, and conduction of heat, which will not happen in space.

There is a high pressure front pushed along by a vehicle moving in an atmosphere. Just before point of contact this will be squeezed between the objects and the increase in pressure will reduce the vehicle speed, just as the wind can. The size of the effect depends on the geometry and mass of the objects.