A toy rocket blasts straight up off the gound with an initial velocity of 50 ft/s. How long will the rocket remain in the air? Use the formula h=-16t^2+50t where h is the height of the rocket in feet and t is the time in seconds after liftoff. Assume no air resistance, and that the rocket has no propelling force after liftoff. Round your answer to the nearest tenth.

Question

campbell_st · Answer

well if h = height, then let h = 0, which means the rocket has no height...on the ground... and solve for t

$$0 = -16t^2 + 50t$$

one answer is t = 0.... which means its on the ground at the start

you can find the other t value by factoring, then solving the binomial factor. 

hope it helps

anonymous · Answer

so then would it be 1.4 seconds idk if i did that right @campbell_st

campbell_st · Answer

well what do you get when you factored the equation..?

anonymous · Answer

25/8 which isnt one of my answer choice @campbell_st

campbell_st · Answer

oops should be 3.125

campbell_st · Answer

or 

3.1 seconds...

anonymous · Answer

thanks!