im working at this lab which involves comparing mumentom of a system before and after an inelastic collision...the trial that the blocks were moving with slower speeds , has a greater percent difference in momentum...i was just wondering if there is any sourse of error in there or is it just normal....the percent difference is doubled in this trial...
2007-11-23 19:56:30 · 3 answers · asked by Ali 4 in Science & Mathematics ➔ Physics
The most likely sources of error--especially when dealing with lower speeds, where it matters--are friction and misaligned impact.
Friction will, naturally, be constant across the experiments no matter what speed you use; but it's based on the mass of the objects and the distance traveled, not the speed. At lower speeds, there will be a higher percentage of frictional differences.
The alignment of the collision will also be important. If the collision is perfectly aligned, the blocks in question can be treated as collision along a line. If not, two-dimensional math will be required, calculating the angle of impact and the resulting vector afterward. Try launching one block at the other without launching the second one; if it hits the other block squarely, it's aligned correctly. Repeat the process with the other block. Also, make sure the intersecting faces are level and square with each other, or the angle of impact will be off, possibly creating rotational motion that can also skew your results.
2007-11-23 20:27:25 · answer #1 · answered by Garon Whited 3 · 0⤊ 0⤋
Assume Mv + mV ? Mv' + mV'; where the masses M and m have momentum based on velocities v and V before impact and momentum based on velocity v' and V' after impact. If elasticity is 1.0, perfectly elastic, then ? is =; otherwise ? is > in the equation above.
Chances are very good that that elasticity < 1.0 in a lab experiment; so that energy will be lost during the collision. In which case, the momentum after the collision will be less than that of the system before the impact. How much less will depend on how inelastic the rebound will be after the impact. In any case, the system velocities will likely be slower on average after the impact than before because of the energy lost to heat etc. from the inelasticity. In which case, we have M(v - v') + m(V - V') > 0.
2007-11-23 20:29:59 · answer #2 · answered by oldprof 7 · 0⤊ 0⤋
Just check the Moment is conserved or not.(Elastic or Inelastic). Also check the Equations using 2D, 3D analysis. In 1Dimension you get errors.
2007-11-23 20:06:51 · answer #3 · answered by kay kay 4 · 0⤊ 1⤋