Question

While filming an action movie, a car drives off a cliff. The function h(t)=-16t^2+40, where t measures the time in seconds, and h (t) gives the car's height above the ground (in feet) as the car falls. Write and solve an equation to determine when the car hits the ground.

Time the car hits the ground:

Answer 1

approximately 1.58 seconds

Explanation:

Set the function h(t)= -16t^2 + 40 = to 0 (the height above the ground when the ball hits). Then solve h(t)= -16t^2 + 40 = 0 for time (t):

-16t^2 + 40 = 0 becomes 16t^2 = 40. Solving for t^2: t^2 = 40/16 = 5/2.

Finally, we take the square root of this last result to determine t:

t = sqrt(10/4) = (1/2)sqrt(10)

The car hits the ground after (1/2)sqrt(10) seconds, or approximately 1.58 seconds.