Question

Write and solve a quadratic equation for the situation below. Choose the answer that has both an equation that correctly models the situation as well as the correct solution for the situation.

Suppose a model rocket is launched from a platform 2 ft above the ground with an initial upward velocity of 150 ft/s. How long will it take the rocket to hit the ground?

a)0= −16t^2+150t+2; t ≈ 9.4 seconds and t ≈-0.01 seconds

b)0= −16t^2+150t+2; t ≈ 9.4 seconds

c)2= −16t^2+150y+2; t ≈ 9.4 seconds

d)None of the choices are correct.

Answer 1

h(t)=gt^2/2+v0t+h0, we let g≈-32, v0=150, h0=2 so

h(t)=-16t^2+150t+2, h=0 when

16t^2-150t-2=0

t=(150±√22628)/32, since t>0

t≈9.39 seconds (to nearest hundredth)