Impulse Lab

In this week's lab, we performed a collision to determine the relationship between force, distance, and time. First, we attached our force probe and zeroed it. Then, we performed a collision between the red cart and the aluminum ring and found the momentum and measured the velocity before and after the collision. We found the velocity before to be 0.2625 m/s and after to be -0.2997 m/s. We measured our force as -.2100 N. Below is an image of our data in LoggerPro:

Through our data and class discussion, we came to the conclusion that impulse is the area of a force vs. time graph. In a collision, the momentum changes because of the impulse, measured in NxS (or force x time). No matter the mass, there is always an equal and opposite force--in any collision. When you increase time, force is always decreased. We found the equation for impulse to be J= Pf - Pi, or impulse= final momentum - initial momentum. Below is an image of our white board:

Real World Connection:

In the real world, the physics behind bowling relate to momentum and impulse. When the bowling ball comes in contact with the pins, a collision takes place. The momentum of the ball, however, changes because of the impulse. The article below further explains this theory:
http://www.topendsports.com/sport/tenpin/physics.htm

Collisions Lab

In this week's lab, we studied the difference between energy lost in an Elastic Collison vs. an Inelastic Collison. To do so, we set up two carts so that their spring launches were facing one another, so ensure that they would bounce off each other for an elastic collision.  Our carts weighed .25 kg. We measured the speed of the red cart to be .472 m/s and the blue cart to be 0 m/s before the collison. After the collision, the red cart had a velocity of .323 m/s and the blue cart to be .243 m/s. Then, we set up the carts so that their velcro sides were facing one another so that they would stick together, for an inelastic collision. We recorded the red cart to have a speed of .667 m/s and the blue cart of 0 m/s before the collision.
After the collision, the red cart had a velocity of
.031m/s and the blue cart of .431 m/s. A table with
our data is shown below:

After our experiment, we calculated the amount of energy for the elastic and inelastic collisions by finding the percent difference, which is the total energy before x the total energy after / the average of total energy before and after x 100.  We calculated the percent difference of energy in the elastic collision to be 19.608 %. The momentum in the elastic collison was 1.709 %. For the inelastic collision, the energy had a percent difference of 94.737 %, and the momentum of 16.181 %. For both types of collisions, momentum had a lower percent difference, so momentum is more conserved and momentum can help us analyze collisions.

Real World Connection: 

Above is an image of a collision in real life and this article desribes the relationship of energy and momentum that causes it. http://toppers-club.com/iit-physics/be-careful-in-applying-law-of-conservation-of-energy/