Oh my lord lol I was do ready to help then I saw numbers
Relative motion means a motion relative to a reference point. We can also say, relative motion means motion referred or observed from a reference point.
For example, Alex is in a train and Ace is at the station, when the train starts moving, for Ace it is moving at a speed of 10 m/s, but for Alex it is moving at 0 m/s, or we can say that it is at rest for Alex, but in motion for Ace. This is relative motion.
On a flat surface a moving bicycle has more kinetic energy than a stationary car
Compression and rarefraction, the other guy's answer it's wrong
DRAG is the sum of all the aerodynamic or hydronamic forces in the direction of the external fluid flow.
