How many seconds will it the for the orange to drop 40 ft?

Question

A person walking across a bridge accidentally drops an orange from a height of 40 ft
h = -16t^2 + 40
h = height
T= seconds
How many seconds will it the for the orange to drop 40 ft

Answer 1

Solve for h(t) = -16t^2 + 40 = 0

16t^2 = 40

t^2 = 40/16 = 2.5

t = √2.5 = 1.58 seconds

Answer 2

You want to know when the height is 0 and hence the orange has dropped all 40 feet to the ground.

0 = -16t² + 40



Add 16t² to both sides:

16t² = 40



Divide both sides by 16:

t² = 40/16

t² = 5/2



Take the square root of both sides:

t = ±√(5/2)



In this case we can ignore a negative time:

t = √2.5

t ≈ 1.58 seconds

Answer 3

s = u t + 1/2 g t ²

Assume initial velocity = 0 ft/s

40 = 0 + 1/2 x 32 t²

80 / 32 = t² = 5 / 2

t = 1•58 sec

Answer 4

-40 = -16t^2

t^2 = 10/4 = 5/2

t = √[5/2] seconds