a partice of mass m strikes elastically on a wall with velocity v , at an angle of 60° from the wall then magnitutude change in momentum of ball along the wall is ?
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Answered by
25
change in momentum along the wall is always zero
kvnmurty:
if friction is zero.. then..
yessz
but in questions no mentioned about friction. then i give this ans
thanks for verification sir
Answered by
9
The wall exerts a force always in a direction perpendicular to the wall, at the point of impact. Along the wall the force exerted is zero. (Assuming a smooth frictionless surface of the wall). If there is friction along the wall between the ball and the wall, then there will be a change in the momentum along the direction of the wall too.
So the change in momentum of the ball along the direction of the wall (parallel to the wall) is zero. (Assuming friction is zero.)
Given the angle of incidence = 30° with the normal to the wall. (60° with the wall).
Perpendicular to the wall, the change in momentum will be:
= m v Cos 30° - (m v Cos 30°)
= 2 m v Cos 30°
So the change in momentum of the ball along the direction of the wall (parallel to the wall) is zero. (Assuming friction is zero.)
Given the angle of incidence = 30° with the normal to the wall. (60° with the wall).
Perpendicular to the wall, the change in momentum will be:
= m v Cos 30° - (m v Cos 30°)
= 2 m v Cos 30°
:-)
along the wall should be zero
or not dear pls clear my doubt
refresh the screen. i modified
if friction is 0, then along the wall it is zero. if there is friction, then it will not be zero.
ok dear lot of thanks. i forget
now i recall
@pankajJat answer is 0
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