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If a football is kicked and it is in the air for 9 seconds, how high does it go?

Guest Jul 29, 2018
 #1
avatar+110 
0

I think this is impossible for people like us. We would need to be a physicist to figure this out... 

I have many questions, like how fast the ball goes, when it is at its peak point. Also, we would need to know the force of gravity, and the angle in which it is kicked. This is science...

MathCuber  Jul 29, 2018
 #2
avatar+27052 
+1

Assume it starts and ends on the ground.  Assume air resistance is negligible.  Then half of the time it will be going up and half coming down.  When it reaches its peak height it will have a vertical component of velocity of v = 0 m/s.  So we can find its initial vertical component of velocity, u, from:

 

v = u + at   where v = 0 m/s, a = -9.8 m/s2 (gravitational acceleration), t = 9/2 s

 

Knowing u we can now use: 

 

v2 = u2 + 2as to find the peak height, s (metres).

Alan  Jul 29, 2018
 #4
avatar+110 
+1

Um...

We would need to know the force of gravity to determine when it hits its peak point...

 

-MathCuber 

P.S I may be wrong i'm only 10...

MathCuber  Jul 29, 2018
edited by MathCuber  Jul 29, 2018
 #5
avatar+27052 
+1

We need to know the gravitational acceleration, which is approximately 9.8 metres per second per second in magnitude.

Alan  Jul 30, 2018
edited by Alan  Jul 30, 2018
 #3
avatar+247 
+2

you can use the second equation of motion s= ut+1/2at^2

here consider that the ball was at rest before kicking . and came to rest after comming to ground

then v=u=0m/s

and a=10m/s^2  (9.8) BECAUSE IT IS UNDER THE INFLUENCE OF GRAVITY.

this is only true if the ball is kicked vertically upward .

but if the ball was in a projectile motion i.e. in a 2D motion then apply the formula

H =v02sin2 θ/2g

H = maximum height (m)

v0 = initial velocity (m/s)

g = acceleration due to gravity (9.80 m/s2)

θ = angle of the initial velocity from the horizontal plane (radians or degrees).

coolcool

Darkside  Jul 29, 2018

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