Question

How many seconds will the ball be going upward if a ball is thrown vertically upward from the ground with an initial velocity of 20 feet per second and `a(t)= -32` feet per second squared?

Answer 1

The ball will continue to go upward until its (upward) velocity `= 0`

The ball's upward velocity is the sum of
its initial upward velocity
plus its upward velocity (really minus its downward velocity) due to gravity.

This velocity will `=0` for a time `t` (in seconds) when
`0 = (20 ft)/(sec) + (-32 ft)/(sec^2)* t sec`

This simplifies to
`t = 5/8 sec.`