# Physics

Q.1 A ball is thrown 233 m upward and then falls back to earth.
Neglecting air resistance, how long will it be in the air? The acceleration of gravity is 9.8 m/s2 . Answer in units of s.

Q.II An object is thrown downward with an initial speed of 17 m/s from a height of 96 m above the ground. At the same instant, a second object is propelled vertically up from ground level with a speed of 22 m/s. At what height above the ground will the two objects pass each other? The acceleration of gravity is 9.8 m/s2 .

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1. It will be in the air twice as long as it takes to fall from 233 meters high
h = (1/2) g t^2
233 = (1/2)(9.8) t^2
solve for t
multiply by two
==========================
height and time the same
h1 = h2
t1 = t2

h = Hi + Vi t - 4.9 t^2
so
h1 = 96 - 17 t - 4.9 t^2
h2 = 0 + 22 t - 4.9 t^2
so
96 -17 t = 22 t
96 = 39 t
t = 96/39 seconds

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