Question

Data Table A

Mass of Cart (kg)	Impulse (N.s)	Velocity (m/s)		Momentum (N.s)		Change in Momentum	% Diff.
		Before	After	Before	After
0.2695	+0.351	- 0.673	+0.659

Data Table B

Mass of Cart + mass bar (kg)	Impulse (N.s)	Velocity (m/s)		Momentum (N.s)		Change in Momentum	% Diff.
		Before	After	Before	After
0.4695	+0.346	-0.377	+0.372

% Difference= 2×(Change in momentum-Impulse)(Change in momentum+Impulse)×100=

Questions

1. What are possible reasons why the change in momentum is different from the measured impulse?
2. How will raising the end of the Dynamics Track give the cart the same acceleration each time?
3. Compare the impulse and force for an abrupt (hard) and a cushioned (soft) collision. Use words and also sketch the force vs. time graphs.

Summary:

Answer 1

What are possible reasons why the change in momentum is different from the measured impulse?

Force exerted on the cart during the collision is not the only one force acting upon the system, infact there is some frictional force, air resistance etc. They create there own different dynamics and and momentum chnage. But impulse is so instanteneoius that these extra force can not cope up with very tiny time. That is why change i momentum and impulse have different value

How will raising the end of the Dynamics Track give the cart the same acceleration each time?

The acceleration is defined by change in speed divided by change in time. It gives same value after collision each time because the horizontal component of the force due to gravity that accelerates the cart down the track is always remain unchanged a tconstant given angle of track elevation.

Compare the impulse and force for an abrupt (hard) and a cushioned (soft) collision. Use words and also sketch the force vs. time graphs.Compare the impulse and force for an abrupt (hard) and a cushioned (soft) collision. Use words and also sketch the force vs. time graphs.

We can study about impulse only when the process is in a sudden, i.e an abrupt(hard) collision. But in both abrupt and cushioned(soft) collision we can observe momentum chnage. The force vs. time graph for a cushioned collision will appear more spread out in time with a lower net force(flat curve), while an abrupt collision will result in a force vs. time peak that is narrow in time and high in net force. If the change in momentum is same for two different types of collisions, then the areas under the force vs. time curves will be same.