Aball is thrown with a horizontal velocity of 80 m/s from the top of a 250 m high building. how long will it be in the air?

19.0 s

Explanation:

Since the motion of the ball is a free-fall motion, we can solve the problem by using the following suvat equation:

where, chosing upward as positive  direction, we have:

s = -250 m is the displacement of the ball to reach the ground

u = +80 m/s is the initial velocity of the ball

t is the time

is the acceleration of gravity

Re-writing the formula we have:

This is a second-order equation, so we solve it by applying the usual formula to find t:

And considering only the positive solution, from the calculation we get

t  = 19.0 s

So, the ball will be in air for 19.0 s.

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