CONSERVATION OF LINEAR MOMENTUM LAB
Objectives
The main goal of this experiment is to verify the conservation of linear momentum and energy during the collision between two masses moving on a "frictionless" track.
Materials
Vernier motion encoder system with cart, motion detector, additional cart with plunger, force probe.
Learning Goals
After this activity you should be able to:
Define and find impulse as the area under the force vs time graph
Connect impulse to the change in momentum during a collision
Distinguish between elastic and inelastic collisions
Calculate the linear momentum of a system before and after the collision
Apply the conservation of linear momentum law to any type of collisions
Collect, analyze and interpret data
Directions
Part I: Impulse and Change in Momentum
In this part you will find the impulse during a collision using the area under the force vs time graph.
1. Set up the Motion Encoder Track on a horizontal surface. The motion encoder is attached to one end of the track. At the far end of the track attach a spring connected to the force probe. Your set up should look like shown below.
2. Place the cart close to the middle of the track and define that position as zero in the software.
3. Set the zero of the force probe when nothing is touching the spring.
4. Measure the mass of the cart using a balance.
5. Push the cart gently toward the spring / force probe combination and start collecting data. The cart collides with the spring and bounces back. The motion encoder collects data on the position and velocity of the cart before and after it collides with the cart. The force sensor connected to the spring collects data on the interaction force between the cart and spring during the time of the collision.
6. The top panel of collected data shows how the force in the spring changes with time during the collision. The two panels at the bottom show how the position and velocity of the cart change before and after the collision of the cart with the spring.
7. Impulse is defined as the area under the force vs time graph. To find this area, use the integral tool in Logger Pro that can be found in the toolbar. Make sure that the integral is calculated only over the collision time. You can adjust the selection of the collision time by moving the two black brackets.
8. Find the velocity of the cart just before and just after the collision using the position vs time graph. Select a very short time interval just before (and just after) the cart collides with the
