Impulse Lab

Big Question
What is the relationship between impulse, force, and time in a collision?

In this week's lab, we collided 2 aluminum rings. One ring was attached to a car and the other on a force probe stand. The rings help to slow down the collision so we could analyze the experiment better. We measured the velocity with the sonic probe.

Data

• Mass of cart=0.25g
• Velocity before collision=0.4833 m/s
• Velocity after collision=-0.4008 m/s
• Area under F v T graph=-0.2580 N/s
• Impulse=area under a F v T graph-->J=Ft OR
• Impulse=change in momentum (Kgm/s)-->J=P final-P initial

Big Question #2
Which ring will bend more? Red car or blue car?

After the lab, we crashed a red car with less mass and a blue car with more mass. Aluminum rings were attached to both of the cars.

The rings bend the SAME amount

In any collision, no matter what the mass, there is an equal and opposite force! Since the red car has less mass, there is a greater change in momentum. Force and time are inversely proportional (increase T, decrease F) but impulse remains constant.

J     =      F      x      T 

(NxS)    (N)          (s)

(Kgm/s) (Kgm/s)  (Kgm/s)

Real Life Connection-Landing in Basketball!

When Michael Jordan goes for a dunk, he later bends his knees when he lands. By bending his knees, it increases the time of him landing which decreases the amount of force created from the force of the floor on his knees. There is an equal and opposite force on his knees and the floor. The impulse will always stay constant.

Collision Lab

Big Questions

• What is the difference between the amount of energy lost in an elastic collision vs. an inelastic collision?
• What is a better conserved quantity-momentum or energy?

In this week's lab, we performed an elastic and an inelastic collision to see how momentum and kinetic energy would be affected. Ms. Tye changed up the purpose of the lab this time! Prior to the lab, we already knew the equation p=mv or momentum=mass x velocity. The purpose of the lab was to prove and understand why momentum is used to analyze collisions. We used two cars with a mass of 0.25 kg each for our experiment. In the elastic collision, the cars collided and bounced off each other due to the spring launchers. In the inelastic collision, the cars collided and stuck together due to velcro. We also learned about scalar and vector quantities. A scalar quantity are simple values without any certain direction (mass, temperature, energy, etc..) A vector quantity measures mass and direction (rightward [+] and leftward [-]) We collected our data on the Vernier program. The dips/ hill represents the car's change in velocity

Here is a chart of both collisions involving velocity, momentum, and kinetic energy.

We also had to find the percent difference for the amount of energy and momentum that entered or left the system.

(total energy after-total energy before/average of total energy before and after) x100

Inelastic Collision

Elastic Collision

• also used for momentum!

We could see that almost all of the energy was lost in the system based on the percent errors. Most of the time, momentum was conserved. Therefore, momentum is better conserved in a collision. Energy is lost due to many factors in a system.

Real Life Connection-Golf!
 When playing golf, the club collides with the tiny golf ball. This is an example of an elastic collision. ENergy is transferred from the club to the ball. We must also remember that energy is lost to many factors in a system and momentum is better conserved.

Rubber Band Cart Launcher Lab

Big Question


How are energy and velocity related?

In this week's lab, we used a photo gate sensor to detect the speed of the glider as it passed through it. The sensor calculates the speed based on how much time the glider blocks the photo gate. We performed 5 trials by stretching the rubber band 5 different distances from 0.1-0.5 meters.

From this lab, I learned that energy is conserved! Energy is transferred from elastic potential energy to kinetic energy. The equation to describe this directly proportional relationship is KE=1/2 (m) (v^2)

Real Life Connection-Archery!
By pulling on the arrow, you are increasing the elastic potential energy. When you release the arrow, the energy transfers and becomes kinetic energy. If you increase the elastic potential energy, you are also increasing the kinetic energy which increases the velocity by which the arrow travels. The KE and the EPE are directly proportional. Energy is not only transferred but, also conserved.