## Videos By Chapter from Inquiries Into Physics

Chapter 3: Energy and Conservation Laws

1. Conservation Laws
2. Linear Momentum
3. Work
4. Energy
5. Conservation of Energy
6. Collisions
7. Power
8. Rotation and Angular Momentum

# Energy and Conservation Laws Videos

### Linear Momentum

Discussion
Streaming
Demo Page
Elastic Collisions, equal mass One cart is at rest when another cart of equal mass hits it. The momentum of the moving cart is transferred to the cart at rest.

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### Conservation of Energy

Discussion
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Loop-de-loop The ball begins at the top of the long end with potential energy. At the bottom of the hill, the energy is all kinetic. At the top of the loop and the top of the short side, the energy is split between potential and kinetic.

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Nose Basher Pendulum: 3rd person view A pendulum can never have more energy than what was originally put into the system. A pendulum released at a person's nose will not hit the person on the return swing.

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Nose Basher Pendulum: 1st person view A pendulum can never have more energy than what was originally put into the system. A pendulum released at a person's nose will not hit the person on the return swing.

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Roller Coaster At various points on the track, the car will have the same total energy, but it will be split into kinetic and potential energies dependent on its height and velocity. The higher the PE, the lower the KE and vice versa.

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### Collisions

Discussion
Streaming
Demo Page
Double Ball Bounce A tennis ball is held in contact with a basket ball, then the two are dropped as one. The basketball has a higher momentum since is has a higher mass. When they hit, the momentum"switches"; i.e. the tennis ball has a momentum equal to that had by the basketball before the collision. The effect is a very fast moving, high bouncing tennis ball.

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Elastic Collisions, equal mass One cart is at rest when another cart of equal mass hits it. The momentum of the moving cart is transferred to the cart at rest.

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Elastic Collisions, B/s mass One cart is at rest when another cart of higher mass hits it. The momentum of the carts are transferred, giving the smaller massed cart a larger velocity.

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Elastic Collisions, s/B mass One cart is at rest when another cart of lower mass hits it. The momentum of the carts are transferred, giving the larger massed cart a smaller velocity.

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Exploding Carts, equal mass Because these carts are of equal mass, they will have the same velocities and momentums after release.

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Exploding Carts, unequal mass Because these carts are NOT of equal mass, they will NOT have the same velocities after release. Instead, their velocities are inversely proportional to their mass; i.e. the bigger mass will have the smaller velocity. Their momentums will still be equal.

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Inelastic Collisions, equal mass In all cases, the two carts stuck together after the collision will have a momentum that is equal to the combined momentum of the two carts before the collision.

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Inelastic Collisions, B/s mass In all cases, the two carts stuck together after the collision will have a momentum that is equal to the combined momentum of the two carts before the collision.

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Inelastic Collisions, s/B mass In all cases, the two carts stuck together after the collision will have a momentum that is equal to the combined momentum of the two carts before the collision.

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MPG In all cases, the momentum of the excited ball(s) will be transferred down the line on balls, exciting an equal amount of balls at the end. For example, one ball given an initial momentum will cause one ball at the opposite end to have the same momentum after collision.

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MPG In all cases, the momentum of the excited ball(s) will be transferred down the line on balls, exciting an equal amount of balls at the end. For example, one ball given an initial momentum will cause one ball at the opposite end to have the same momentum after collision.

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MPG In all cases, the momentum of the excited ball(s) will be transferred down the line on balls, exciting an equal amount of balls at the end. For example, one ball given an initial momentum will cause one ball at the opposite end to have the same momentum after collision.

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MPG In all cases, the momentum of the excited ball(s) will be transferred down the line on balls, exciting an equal amount of balls at the end. For example, one ball given an initial momentum will cause one ball at the opposite end to have the same momentum after collision.

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MPG In this case, the momentum of the excited ball is transferred to the other ball of equal mass. The velocity of the second ball after collision is the same as the first's before the collision due to the conservation of momentum.

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Newton's Cradle, big and small ball In this case, the larger massed ball has a low velocity. When the momentum is transferred to a lower mass ball, the velocity must go up in order to maintain the conservation of momentum.

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MPG In this case, the momentum of the large excited ball is transferred to balls at the end. The momentum is split primarily between the end three balls, the two inner ones each having a velocity equal to 1/2 of the previous. This gives rise to the doubling in distance seen between the end balls.

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MPG This demo is a combination of explosive collisions and inelastic collisions. Each roller blader gains momentum with each toss AND catch of the pillow.

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### Rotation and Angular Momentum

Discussion
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Demo Page
Bicycle Wheel and Rotating Platform The force created by a turning wheel will cause the person on the platform to turn in order to conserve angular momentum. In this case, the wheel begins vertically and the person will rotate left or right depending on the tilt of the wheel.

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Bicycle Wheel and Rotating Platform 2 The force created by a turning wheel will cause the person on the platform to turn in order to conserve angular momentum. In this case, the wheel begins horizontally. Turning it vertical makes the person spin, turning it completely over makes the person's speed double.

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Bicycle Wheel Gyroscope Outside torques produced by gravity and friction cause the wheel to be vertical and spin about the axle in order to conserve angular momentum. This is why it's easier to stay on a moving unicycle or bicycle than a stationary one.

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Person and Rotating Platform Due to the conservation of angular momentum, when the rotating person brings the masses closer to his body, he will rotate faster. We have all seen this in figure skating.

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