Momentum and Collision

Objectives:

• To investigate and calculate momentum

Key Terms:

• displacement
• velocity
• momentum
• friction
• collision

Pre Lab Discussion:

What is momentum and how is it calculated?

Momentum can be defined as "mass in motion", or the quantity of motion an object has. All objects have motion so, if they are in motion, they had momentum. Momentum can be calculated with the formula: m(mass) * v(velocity) = P(momentum)

Here's the video that we used (Mr. Eschelbacher's new hit single: Momentum & Collisions Lab ft. Vernier)

https://www.youtube.com/watch?v=3VyBnJRSzZo

Materials:

• Two Vernier cars
• Car track
• LabQuest
• Two motion detectors

Trials and Graphs:

TWO COLLIDING

Beginning 

During 

End

PERCENT DIFFERENCE: 

ONE AT REST, ONE IN MOTION 

ONE AT REST, ONE IN MOTION: VELCRO

Analysis:

Graph 1: 

This graph analyzes the velocity of the cars before they collide. We know the mass of the cars (0.5098 kg) and the velocities before the crash. With this, we can calculate their momentum: 

Car 1: m*v = (0.5098 kg) * (.3462 m/s) = 0.1765 kg*m/s

Car 2: m*v = (0.5098 kg) * (-0.3583 m/s) = -0.1827 kg*m/s

Net Momentum: P1+P2= -0.0062 kg*m/s

Total Momentum: |P1+P2| = 0.3592 kg*m/s

Graph 2:

Collision

Car 1: m*v = (0.5098 kg) * (-0.0415 m/s) = -0.0212 kg*m/s

Car 2: m*v = (0.5098 kg) * (.1239 m/s) = 0.0632 kg*m/s

Net Momentum: P1+P2= 0.0042 kg*m/s

Total Momentum: |P1+P2| = 0.0844 kg*m/s

Graph 3:

End of collision. This data depicts the momentum lost due to friction. Friction slows the velocities of the cars, therefore changing the momentum. 

Car 1: m*v = (0.5098 kg) * (-0.2469 m/s) = -0.1259 kg*m/s

Car 2: m*v = (0.5098 kg) * (0.2136 m/s) = 0.1089 kg*m/s

Net Momentum: P1+P2= -0.017 kg*m/s

Total Momentum: |P1+P2| = 0.2348 kg*m/s

Graph 4:

Graph four depicts the transfer of momentum from the moving cart to the stationary cart. The velocity of the first cart is zero and the velocity of the second cart equals the magnitude of the first cart prior to the collision. 

Graph 5:

In graph five, due to the Velcro on the carts, the two carts collide and essentially become one entire mass, meaning they share the same velocity after the collision. Though the velocity may be reduced by half, it is simply because the mass has doubled (0.5098 kg * 2) in the collision. Momentum is still conserved. 

Overall Analysis:

This lab has shown us the beginning, middle, and after aspects of a collision. With friction taken in to account, is it clear that momentum is a conservative force and can be transferred between two objects. Momentum is, again, the quantity of motion an object has and can be calculated by multiplying the mass by the velocity. This humorous gif explains how momentum changes: