- #1
vissh
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heya :)
(Q)A ball of mass m is dropped onto a floor from a certain height. The collision is perfectly elastic and the ball rebounds to the same height and again falls. Find the average force exerted by the ball on the floor during a long time interval.
>Change in linear momentum of body = [tex]\int[/tex]Fdt
.....where F is the net force on the body during the collision
>Velocity of separation = e (Velocity of appraoch)
>As the ball is abt to strike, its velocity v = (2gh)1/2
>The ball will exert force when it hits the floor and impulse of that force will be approximately equal to [neglecting impulse by gravity] "Change in momentum of Ball".
Thus, [tex]\int[/tex]Fdt = mv-(-mv) = 2mv
-- Now as we are talking abt The Average force , Fav (let) , so it can be taken out of integration for it to be const on the time interval.
Thus, Fav [tex]\int[/tex]dt = 2mv
--Now,the problem is that i can't decide what will be the required time interval.
Need a bit guidance in this ^.^
The answer of prob is Fav = mg [if u need xD hehe]
Thanks in advance :)
Homework Statement
(Q)A ball of mass m is dropped onto a floor from a certain height. The collision is perfectly elastic and the ball rebounds to the same height and again falls. Find the average force exerted by the ball on the floor during a long time interval.
Homework Equations
>Change in linear momentum of body = [tex]\int[/tex]Fdt
.....where F is the net force on the body during the collision
>Velocity of separation = e (Velocity of appraoch)
The Attempt at a Solution
>As the ball is abt to strike, its velocity v = (2gh)1/2
>The ball will exert force when it hits the floor and impulse of that force will be approximately equal to [neglecting impulse by gravity] "Change in momentum of Ball".
Thus, [tex]\int[/tex]Fdt = mv-(-mv) = 2mv
-- Now as we are talking abt The Average force , Fav (let) , so it can be taken out of integration for it to be const on the time interval.
Thus, Fav [tex]\int[/tex]dt = 2mv
--Now,the problem is that i can't decide what will be the required time interval.
Need a bit guidance in this ^.^
The answer of prob is Fav = mg [if u need xD hehe]
Thanks in advance :)