Question

A ball is thrown upward in the air, and its height above the ground after t seconds is H ( t ) = 63 t − 16 t 2 feet. Find the time t when the ball will be traveling upward at 15.75 feet per second.

Answer 1

Answer:

1.477seconds

Explanation:

The height of the stone thrown in air after t secs is expressed by the equation;

H(t) = (63t − 16t²) feet

Velocity is the change in displacement of the body with respect to time.

V(t) = d(H(t))/dt

V(t) = 63 - 32t

To get the time t when the ball will be traveling upward at 15.75 feet per second, we will substitute V(t) = 15.75 into the resulting equation as shown;

15.75 = 63 - 32t

-32t = 15.75-63

-32t = -47.25

t = 47.25/32

t = 1.477seconds

Hence the ball will be travelling upward when t is 1.477s