An object is kicked from a platform. The equation h = - 4.9 t 2 + 7 t + 9

Question

An object is kicked from a platform. The equation $h = - 4.9 t^{2} + 7 t + 9$ represents this situation, where $h$ is the height of the object above the ground, in meters, $t$ seconds after it is kicked. Which number represents the height, in meters, from which the object was kicked?

A.

$0$

B.

$4.9$

C.

$7$

D.

$9$

Accepted Answer

Choice D is correct. It&rsquo;s given that the equation h = - 4.9 t 2 + 7 t + 9 represents this situation, where h is the height, in meters, of the object t seconds after it is kicked. It follows that the height, in meters, from which the object was kicked is the value of h when t = 0 . Substituting 0 for t in the equation h = - 4.9 t 2 + 7 t + 9 yields h = - 4.9 0 2 + 7 0 + 9 , or h = 9 . Therefore, the object was kicked from a height of 9 meters. Choice A is incorrect and may result from conceptual or calculation errors. Choice B is incorrect and may result from conceptual or calculation errors. Choice C is incorrect and may result from conceptual or calculation errors.

Question an-obj