If a projectile is launched vertically upward from the ground with an initial velocity of 70 ft per sec, neglecting air resistance, its height s (in feet) above the ground t seconds after projection is given by s equals negative 16 t squared plus 70 t. which equation should be used to determine the time at which the height of the projectile reaches 10 ft?

Step-by-step explanation:

Given that a projectile is launched vertically upward from the ground with an initial velocity of 70 ft per sec

Neglecting air resistance, its height s (in feet) above the ground t seconds after projection is given by

When height = 10 feet we have to find the time

Hence substitute s = 10 ft

We may get two answers as

The first time is for going up and the second is for coming down.

answer: a.

step-by-step explanation: the answer is a. because, you need to converge the fractions to find a solution.