2007-11-08 23:13:08 · 3 answers · asked by yashvi s 2 in Science & Mathematics ➔ Physics
we cannot! certainly we can't consereve the total momentum when we've got the friction!
2007-11-08 23:21:41 · answer #1 · answered by Anonymous · 0⤊ 0⤋
During collision by Newton's third law of motion , if A exerts a force on B , then B exerts an equal but opposite force on A.
And we know both are in contact for a brief period t.
Force x time is the change in momentum.
Since force and time are the same for both objects A and B, change in momentum in A and change in momentum of B are equal.
If friction is present force exerted by one on the other will be less than in the previous case. Hence there will be less change in momentum than the previous case. However change in momentum of A will be the same as the change in momentum of B.
Therefore even when there is friction, there is conservation of momentum
On the other hand the kinetic energy will not be conserved because of friction. In ideal elastic collision where we consider that there is no friction , kinetic energy is also conserved.
2007-11-09 07:39:16 · answer #2 · answered by Pearlsawme 7 · 1⤊ 0⤋
Collision analysis is usually idealized to occur in zero time. Thus there is no motion in that instant so no friction loss.
In actuality there is some motion (compression/rebound in elastic, crumpling in inelastic) and some friction loss does occur in addition to any inelastic losses. Most textbook problems about 'real' collisions ignore friction even if asking for details of motion during the collision.
2007-11-09 09:06:46 · answer #3 · answered by kirchwey 7 · 0⤊ 0⤋