Astone thrown horizontally from a height of 5.72 m hits the ground at a distance of 13.30 m. calculate the initial speed of the stone. neglect air resistance.

initial velocity=12.31 m/s

Final speed= 16.234 m/s

Explanation:

Given Data

height=5.72 m

distance=13.30 m

To Find

Initial Speed=?

Solution

Use the following equation to determine the time of the stone is falling.  

d = vi ×t   ½ ×9.8 × t²

Where  

d = 5.72m and vi = 0 m/s

so  

5.72 = ½× 9.8 ×t²

t = √(5.72 ÷ 4.9)

t=1.08 seconds

To determine the initial horizontal velocity use the following equation.

d = v×t

13.30 = v ×1.08

v = 13.30 ÷ 1.08

v=12.31 m/s

To determine stone’s final vertical velocity use the following equation

vf = vi+9.8×tvi=0 m/s

vf = 9.8×1.08

vf= 10.584 m/s

To determine stone’s final speed use the following equation  

Final speed = √[Horizontal velocity²+Final vertical velocity²]

Final speed = √{(12.31 m/s)²+(10.584 m/s)²}

Final speed= 16.234 m/s

if the person is shown to have +90n, then ans is -10n.

if the person is shown to have -90n, then ans is +10n.