Ph ET Collision Lab - Grade: A PDF

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PhET Collision Lab Maliha RashidPart 1Scenario #1:Elastic collision between balls of equal mass-Make a hypothesis about initial and final momentums before playing with the sim.I think the initial momentum of the balls of equal mass would be that they start from the sameapproximate area, like in the ...

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PhET Collision Lab Maliha Rashid Part 1 Scenario #1: Elastic collision between balls of equal mass -Make a hypothesis about initial and final momentums before playing with the sim. I think the initial momentum of the balls of equal mass would be that they start from the same approximate area, like in the middle. I think the final momentums of the balls of equal mass is that they will be in similar areas at the end? Or close to one another. - Make a data table for the following: mass, velocity and momentum of each ball before and after.

1

Mass

Velocity (initial)

Velocity

Ball 1: 0.5 kg Ball 2: 0.5 kg

Ball 1: Vx= 1 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: Vx= -0.500 Vy= 0 Ball 2: Vx= -1.0 Vx= 0

Ball 1: Vx= 1 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: Vx= -0.500 Vy= 0 Ball 2: Vx= 1.0 Vx= 0

Ball 1: 1

Ball 1: -0.50

Ball 2: -0.5

Ball 2: 1.0

Ball 1: Vx= 1.5 Vy= 0 Ball 2: Vx= -0.75

Ball 1: Vx= -0.500 Vy= 0 Ball 2: Vx= -1.0

Ball 1: 1.5

Ball 1: -0.70

Ball 2: -0.65

Ball 2: -1.5

Time: 1.29s

2

Ball 1: 1 kg Ball 2: 1 kg Time: 1.23s

3

Ball 1: 1.5 kg Ball 2: 1.5 kg Time: 1.26s

Momentum (initial)

Momentum (final) Ball 1: -0.250

Ball 1: 0.5

Ball 2: -0.50

Ball 2: -0.25

4

Ball 1: 2 kg Ball 2: 2 kg Time: 1.24s

Vx= 0

Vx= 0

Ball 1: Vx= 1 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: Vx= -0.500 Vy= 0 Ball 2: Vx= -1.0 Vx= 0

Ball 1: 2

Ball 1: -1.0

Ball 2: -1.0

Ball 2: -2.0

-What is the relationship between the initial and final total momentums? Describe the motion of the balls before and after the collision? While collecting data, I noticed that every time the balls hit (bounce back) on one another the next time and when they hit the wall, the momentum always changes. Momentum is the quantity of motion of a moving body that is measured by its product of mass and velocity. I also noticed that the Vx always changed as well once the balls hit each other or even the wall. The relationship between the initial and final total momentum is that they both will not be at rest after they both hit each other (collided). Also when collecting data, the momentum was never zero at the beginning of the test, it always varied depending on the mass of the balls. The motion of the balls before and after the collision was that when collecting data from the mass of 0.5kg balls, I noticed that the red ball (ball 1) was moving faster towards the green ball (ball 2) than the green was moving towards the red. Once they collided, the green ball was moving at a faster speed than the red and was nearly catching up to the red ball that was going its opposite direction. This is the same for all the other masses of data I had previously collected above. Scenario #2: Elastic collision between balls of unequal mass. - Make a hypothesis about initial and final momentums before playing with the sim. - Make a data table for the following: mass, velocity and momentum of each ball before and after.

-What is the relationship between the initial and final total momentums? Describe the motion of the balls before and after the collision? Since now the masses are unequal, I hypothesize that the initial momentums will also be different but not zero and the final momentums will be different from one another as well.

1

Mass

Velocity

Momentum (initial)

Momentum (final)

Ball 1: 0.5 kg Ball 2: 1 kg

Ball 1: Vx= -1.0 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: 0.50

Ball 1: -0.50

Ball 2: -0.50

Ball 2: -0.50

Ball 1: Vx= -1.0 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: 1

Ball 1: -1.0

Ball 2: -1

Ball 2: -1.0

Ball 1: Vx= -0.909 Vy= 0 Ball 2: Vx= 0.591 Vx= 0

Ball 1: 2

Ball 1: -1.818

Ball 2: -1.7

Ball 2: 2.068

Ball 1: Vx= 0.826 Vy= 0 Ball 2: Vx= -0.674 Vx= 0

Ball 1: 4.5 Ball 2: -3.5

Ball 1: 3.717

Time: 1.85s

2

Ball 1: 1 kg Ball 2: 2 kg Time: 1.82s

3

Ball 1: 2 kg Ball 2: 3.5 kg Time: 1.71s

4

Ball 1: 4.5 kg Ball 2: 7 kg Time: 1.24s

Ball 2: -4.717

After collecting this data I was right about the initial and final momentums not being the same. In all four tests, the momentums came out a different number than before. While collecting this data, I noticed that the smaller the ball the faster it will be. All of these data done are collections of elastic collisions since they bounce back from one another and don’t stick to one another or lose kinetic energy. The motions of the balls after collision was that the smaller the mass of the ball, the faster it will move, the smaller ball will collide itself with the bigger ball more than the bigger ball will collide itself with the red ball. Since it moves more slowly the weight is impacting its speed. Its like they feed energy off one another since the final momentum is completely different from its initial momentum. Part 2 Create 3 more distinct scenarios in 1-d including one totally inelastic collision. Make a hypothesis whether or not each will follow conservation of momentum. Collect some data and prove or disprove your hypothesis. Summary: Describe the main ideas learned in this activity regarding initial and final total momentum in 1-d collisions. Hypothesis: I do not think I can try to create one totally inelastic collision but I will do my best and I do not think that these three scenarios will conserve momentum because looking back at my other data, none of them did. Mass

Velocity (initial)

Velocity (final)

Momentum (initial)

Momentum (final)

1

Ball 1: 1 kg Ball 2: 3 kg

Ball 1: Vx= 1 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: Vx= -1.250 Vy= 0 Ball 2: Vx= 0.250 Vx= 0

Ball 1: 1 Ball 2: -1.5

Ball 1: -1.25 Ball 2: 0.75

2

Ball 1: 2 kg Ball 2: 1 kg

Ball 1: Vx= 1 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Ball 1: Vx= 0 Vy= 0 Ball 2: Vx= 1.5 Vx= 0

Ball 1: 2 Ball 2: -0.5

Ball 1: 0 Ball 2: 1.5

3

Ball 1: 10 kg

Ball 1:

Ball 1:

Ball 1: 10

Ball 1: -8.0

Ball 2: 15 kg

Vx= 1 Vy= 0 Ball 2: Vx= -0.5 Vx= 0

Vx= -0.8 Vy= 0 Ball 2: Vx= 0.7 Vx= 0

Ball 2: -7.5

Ball 2: 10.5

My hypothesis was correct that there was no conservation of momentum since they all changed and were not the same at the end. It was hard to try to make it totally inelastic since the balls were not even close to sticking on to one another. Simmary: The main ideas learned regarding initial kinetic energy is that when the balls collide, some fraction of that energy is being converted into something else, some other form of energy. I think it was energy during the collision or heat energy. But this would be inelastic collisions occurring. The initial and final momentum is that two objects will come at each other with either equal or opposite momentums and then diverge onto the opposite sides just exactly like how the balls were doing with equal or opposite momentums at the final. The data I was collecting, the initial and final momentums were not the same but opposite. The center of mass will also be conserved in since the energy and momentum were conserved in the small rectangle with the 2 balls....