A hang glider dropped his cell phone from a height of 350 feet. How many seconds did it take for the cell phone to reach the ground?

Question

4648 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-06-17T21:53:53

#t = 4.68 s#

Assuming negligible air drag, it was in free fall (g = 32 ft/s^2) for the entire 350 feet. So we use the formula

#y = u*t + 1/2*a*t^2#

Plugging in the data

#350 ft = 0 + 1/2*(32 "ft")/s^2*t^2#

#350 ft = (16 ft)/s^2*t^2#

#t^2 = (350 cancel(ft))/((16 cancel(ft))/s^2) = 21.88 s^2#

#t = sqrt(21.88 s^2) = 4.68 s#

I hope this helps,
Steve