Afriend is riding on the back of a truck that is going away from you at 20 km/h. as the truck passes, your friend throws a ball toward you at 60 km/h relative to her. how fast is the ball going relative to you?

Since the ball moves in the relative direction opposite to the displacement of the car, the speeds must be subtracted, so

Both move opposite directions. The attached graphic helps to better appreciate the problem in question, which concludes that the relative speed is 40km / s

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

hope this ! : )

a=d/t

a="triangle"v/t

explanation:

a = acceleration