Afootball player running at two meters per second dives towards a football flying towards him with a velocity of five meters per second. what is the relative velocity of the football player and the football?
a. 0 m/s
b. 2 m/s
c. 5 m/s
d. 7 m/s

option d.

Explanation:

In this situation, we can suppose that the football player has a velocity of 2m/s in the positive x-axis, and the ball has a velocity of -5m/s in the x-axis.

If we step in the point of view of the football player, all the previous x-axis now moves with the same velocity that the player had, but in the other direction, so all the axis now moves with a velocity of -2m/s. And the ball that also is in the axis also gets this "boost" in velocity.

So now the velocity of the ball is -5m/s -2m/s = -7m/s where the minus sign is because of the situation that I crafted.

So the correct option is the option D