Question

The height, h, in feet, of an object abovd the ground is given by h(t) = -16t²+64t+190 Find the time it takes for the object to strike the ground?

Answer 1

5.98 SECONDS

Explanation:

h(t) = -16t²+64t+190

h(t) when the object strikes the ground is 0 (ground is defined as 0 height)

So we want t such that h(t) = 0

0 = -16t²+64t+190

Solve using the quadratic formula. Two solutions are found:

-1.98 and 5.98

We aren't given units, but it might be safe to say the time is in seconds. The negative value (going back in time) doesn't make sense in this problem, so we can drop it.

The object will strike the ground in 5.98 seconds.

From the equation, we can see that it starts at 190 (feet?) and that it accelerates downward at 16 (feet/sec?). The 64t tells us the object already has some velocity at the time it is dropped.