Question

A person standing on the edge of a cliff at some height above the ground throws first ball straight up with initial velocity, u, and then throws second ball straight down with the same initial velocity u. Which of the following statement is TRUE regarding their velocities when they hit the ground?

• A. Both balls will have same velocity when they hits the ground
• B. First ball will have larger velocity than second
• C. Second ball will have larger velocity than first
• D. Can't say as final velocity depends on other quantities as well

Answer 1

The correct option is A

Both balls will have same velocity when they hits the ground

First ball velocity = +u Second ball's velocity = -u

When first ball reaches to the same height as cliff while coming down. It will have velocity as -u. (as g=9.8m/s² is constant and always downwards)

Hence both balls will have same final velocity