Question

A ball is kicked with an initial horizontal speed of 13.1 m/s from a roof with a height of 3.3 m above the ground, as shown in the diagram. What horizontal distance will the ball travel before hitting the ground, in units of meters?

assume the ground is flat

assume that air resistance is negligible

Answer 1

First find the time of flight

Consider motion in vertical direction

initial vertical velocity =0m/s

acceleration =g

height or vertical distance to cover =3.3m

Use formula

$s=0*t+1/2gt^{2}$

$3.3m=0.5*9.81t^{2}$

$3.3/4.905=t^{2}$

$t=0.82s$

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Since there is no acceleration in horizontal direction ,horizontal speed remains constant

Horizontal speed =Horizontal distance /time

$v_{x}=x/t$

$v_{x}*t=x$

ANSWER: $x=10.742m$

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