Question

If an object is projected upward with an initial velocity of 129 ft per sec, its height h after t seconds is h = -16^2+123t. Find the height of the object after 4 seconds.

Answer 1

Answer: 236ft.

Step-by-step explanation: To solve the given problem, we need to substitute the given time (4 seconds) in the equation to calculate the height of the object with an initial velocity of 129ft per sec. The substitution is shown as follow:

`h=-16^(2) +123t`

`h=-16^(2) +123(4)`

h=-256+492

h=236ft.

The height of the object after 4 seconds is 236ft.

Answer 2

This problem can be solved directly by neglecting the initial velocity given. All we have to do is to plug in t = 4 in the given equation. That is:

h = -16^2 + 123 * 4

h = 236 ft