A toy rocket is shot vertically upward from the ground. Its distance in feet from the ground in t seconds is given by s(t) = -16t^2 + 142t. At what time or times will the ball be 140 ft from the ground? round your answer to the nearest tenth, if necessary.

The ball will be 140 ft from the ground when t = 1.1s and when t = 7.7s

Step-by-step explanation:

To solve this question, we need to understand how to solve a quadratic equation.

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

.

This polynomial has roots such that , given by the following formulas:

The position of the pall is given by the following equation.

At what time or times will the ball be 140 ft from the ground?

This is t when

So

So

The ball will be 140 ft from the ground when t = 1.1s and when t = 7.7s

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