Question

An arrow is shot straight up with a speed of 225m/s. Ignoring air resistance, solve for one of the two times when the arrow is at a height of 564.2 meters?

Answer 1

S = Vo t + 1/2 g t^2 where g is in opposite direction to Vo

564.2 = 225 t - 4.9 t^2

4.9 t^2 - 225 t + 564.2 = 0

t^2 - 45.92 + 115.1 = 0 quadratic equation

t = 2.665 one solution

Check:

225 * 2.665 - 4.9 * 7.102 = 564.8 would need more significant figures for exact match