Measure a cart’s momentum change and compare to the impulse it receives.
Compare average and peak forces in impulses.
Preliminary questions
1.In a car collision, the driver’s body must change speed from a high value to zero. This is true whether or not an airbag is used, so why use an airbag? How does it reduce injuries?
The body can either stop with a small amount of time by hitting something hard or stop slowly with an extended amount of time when hitting something hard. Airbags are used to lower the amount of force pushing on your body when you hit a collision. The airbag allows your body to slow down on a cushion with much less force hitting you. The airbag also pushes you back once you hit it.
2.You want to close an open door by throwing either a 400 g lump of clay or a 400 g rubber ball toward it. You can throw either object with the same speed, but they are different in that the rubber ball bounces off the door while the clay just sticks to the door. Which projectile will apply the larger impulse to the door and be more likely to close it? It would be the rubber ball.Newton’s third law states opposite and equal reaction on each action.The clay ball would stick to the door, that means that the door would only be pushed at the time of impact and only move a slight bit.Meanwhile, the rubber ball bounces off the door so there are basically two forces, one when the ball hits the door and second one when the ball bounces off the door and pushes the door to close. The door did not just stop the ball, but also exerted force to push the ball back.
Analysis 1. If the impulse-momentum theorem is correct, the change in momentum will equal the impulse for each trial. Experimental measurement errors, along with friction and shifting of the track or Force Sensor, will keep the two from being exactly the same. One way to compare the two is to find their percentage difference. Divide the difference between the two values by the average of the two, then multiply by 100%. How close are your values, percentage-wise? Do your data support the impulse-momentum theorem?
My percentage values are not close, because this was not done with the best equipment best fit for this type experiment. I believe my data does support this theorem, that is with the margin for mistakes.
2. Look at the shape of the last force vs. time graph. Is the peak value of the force significantly different from the average force? Is there a way you could deliver the same impulse with a much smaller force? A large force that acts for a short period of time can produce the same change in linear momentum as a small force acting for a greater period of time.
3. When you use different elastic materials, what changes occurred in the shapes of the graphs? Is there a correlation between the type of material and the shape?
If the material used would not be a rubber band, but a piece of rope, the car would not be pulled back, that means the bump on the graph would rise, but not fall. If two rubber bands were used the bump on the graph would not be as steep because the cart would have twice as much tension to pull.
4.When you used a stiffer or tighter elastic material, what effect did this have on the duration of the impulse? What affect did this have on the maximum size of the force? Can you develop a general rule from these observations?
We did not use double elastic, but if we were to, the more tension you add the less distance it goes. A general rule would be the more tension you add the more weight the cart or the object has to pull, so that means that the time frame will be expanded, but the final velocity will not be as high.
5.From the mass of the cart and change in velocity, determine the change in momentum as a result of the impulse. Make this calculation for each trial and enter the values in the second data table. 6.If you used the average force (non-calculus) method, determine the impulse for each trial from the average force and time interval values. Record these values in your data table. 7. Revisit your answers to the Preliminary Questions in light of your work with the impulse-momentum theorem.