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A ball is thrown horizontally from the top of a building 45 m high.

Calculate what is the time taken to reach the ground.

User Tnunamak
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1 Answer

2 votes

Step-by-step explanation:

we assume that "thrown" simply means "released".

that means only gravity is pulling the ball down.

if it were actually "thrown down, there would be a different force and a different initial speed applied.

since you used meters for the height of the building, I also assume that we use only the metric system for everything. and that we are talking about the Earth and Earth's gravity.

so, we know :

the speed of the falling ball as function of time is

v = 9.8 m/s² × t

and the distance traveled is

d = ½ × 9.8 m/s² × t²

we know d = 45 m

and we get

45 = ½ × 9.8 m/s² × t²

90 = 9.8 m/s² × t²

t² = 90/9.8 = 9.183673469...

t = sqrt(9.183673469...) = 3.030457634... sec

it took the ball 3.030457634... seconds to reach the ground.

User Feralin
by
8.2k points

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