This is a measure of force per unit area.

Pressure is the force exerted by a gas, a liquid or a solid on a surface (or area) .

Its unit according to the International System of Units is Pascal which is equal to and its formula is:  

electromagnetic waves travel through space with vacuums. give me brainliest if right.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.