If an object is dropped from a height of 200 feet, the function h(t)=-16t^2+200 gives the height of the object after t seconds. Approx. when will the object hit the ground? I would like an explanation on how to do this please.

Question

welshfella · Answer

when it hits the ground h(t)  equals 0.
so you need to solve the equations
-16t^2 + 200 -= 0

solve for t

welshfella · Answer

do you get that?

dinomancer · Answer

Did you mean to put the negative before the equal sign?

anonymous · Answer

kek

dinomancer · Answer

Still don't really understand this, if anyone could lend a hand that would be great.

aveline · Answer

Ok, here's the equation: h(t)=-16t^2+200
This means that after 0 seconds, the object is at 200 feet above the ground. The variable h(t) resembles the height above the ground. We want that to be 0.
So, 0=-16t^2+200
First, subtract 200 from both sides
-200=-16t^2
Next, divide by -16
12.5=t^2
Finally, square root
√12.5=t

The object will hit the ground after about 3.54 seconds.

dinomancer · Answer

Thanks, I totally understand this now :D

welshfella · Answer

No the negative was a typo