Answer:
The cell phone took 4.7 seconds to reach the ground.
Step-by-step explanation:
A hang glider dropped his cell phone from a height of 350 feet:
Initial velocity: Vo = 0 ft/s
Height: h = 350 feet = 350 ft
Time to reach the ground: t=?
Gravity's acceleration: g = 32 ft/s^2
h = Vo t + g t^2 / 2
Replacing the known values in the equation above:
350 ft = (0 ft/s) t + (32 ft/s^2) t^2 /2
350 ft = 0 + (16 ft/s^2) t^2
350 ft = (16 ft/s^2) t^2
Solving for t^2: Dividing both sides of the equation by 16 ft/s^2:
(350 ft) / (16 ft/s^2) = (16 ft/s^2) t^2 / (16 ft/s^2)
21.875 s^2 = t^2
Solving for t: Square root both sides of the equation:
sqrt(21.875 s^2) = sqrt(t^2)
4.677071733 s = t
t = 4.677071733 s
Rounding to the nearest tenth:
t = 4.7 s
