Purpose: How is the force felt during a collision related to the duration of the collision?
The force felt during the collision is directly related to the mass of the object multiplied by the rate of change in velocity over time.
Analysis:
1. Why is it desirable to have the same initial speed for each data run?
With the same initial speed, it is easier to see where the changes in data could be coming from, if there are any at all. It shows any data differences are the result of some other factor besides the initial speed. (However, this only works when the initial speeds are the same.)
2. How will raising the end of the Dynamics Track give the cart the same acceleration each time?
If the track was level (with an angle of 0 degrees to the tabletop) we would have to exert force onto the cart to get it to move and have an impact. It is very difficult, if not impossible for a human to reproduce the exact same velocity numerous times, Therefore, it is easier to just let gravity do the work instead since it is a constant. The only way gravity will affect the cart is if the track is at an angle to the tabletop. Gravity being a constant will ensure that the initial speeds will be extremely close to each other if not the same.
3. For your data, how does the change in momentum compare to the impulse?
For the 1st run, the difference between the change in momentum and impulse was 0.235 Ns (Newtonseconds), with impulse being greater.
For the 2nd run, the difference between the change in momentum and impulse was 0.085 Ns with change in momentum being greater.
For the 3rd run, the difference between the change in momentum and impulse was 0.165 Ns with impulse being greater.
For the 4th run, the difference between the change in momentum and impulse was 0.110 Ns with change in momentum being greater.
For the 5th run, the difference between the change in momentum and impulse was 0.110 Ns with impulse being greater.
The values for impulse have a range from 0.24-0.57 Ns while the values for change in momentum range from 0.335-0.350 Ns.
4. What are possible reasons why the change in momentum is different from the measured impulse?
One possible reason for the different values could be from the fact that momentum deals with the change in distance over time while force (impulse) deals with change in velocity over time. Also the frictional force of the cart moving up/down the incline is a factor in the inconsistencies between the change in momentum and impulse.
5. Compare the impulse and force for an abrupt (hard) collision and a cushioned (soft) collision.
An abrupt collision would result in an immediate increase in force while a soft collision would result in a gradual increase in force.
6. Using the above reasoning, explain why airbags in cars can help to prevent injuries to the occupants during a frontal collision.
Immediate increase in force would result in extreme stress and pressure to the body thus making the injuries acquired more severe. Gradual increase in force, allowing the force to spread out over time, enables the body time to adjust to the pressure applied. This will decrease the severity of injuries sustained.
