Homework Assignment

Question

NASA launches a rocket at T=0 seconds. Its height, in meters above sea-level, as a function of time is given by . h(t)=-4.9t^2+151t+87

Assuming that the rocket will splash down into the ocean, at what time does splashdown occur?

The rocket splashes down after   seconds.

Answer 1

h(t) = -4.9t² + 151t + 87

The rocket splashes down when the height is zero.

-4.9t² + 151t + 87 = 0

t = (-151 ± √[(151)² - 4(-4.9)(87)] ) / (2(-4.9)) = ( -151 ± √39853) / (-9.8) = -0.57 sec or 31.38 sec

Since time can't be negative, t ≈ 31.38 sec.

Answer 2

h(t) = - 4.9t² + 151t + 87 = 0; t = 31.3821 s