Read the following information on momentum. Once you have read the information, follow the link at the bottom to answer the momentum questions.
Momentum
If a compact car and large truck are traveling with the same velocity, it takes longer for the truck to stop than it does for the car if the same braking force is applied. Likewise, it takes longer for a fast moving car to stop than it does for a slow moving car with the same mass. The truck and the fast moving car have more momentum than the compact car and the slow moving car.
Momentum is a property of a moving object that depends on the object’s mass and velocity. The more momentum an object has, the harder it is to stop the object or change its direction.
Although the compact car and the truck are traveling with the same velocity, the truck has more mass and therefore more momentum, so it is harder to stop than the car. Similarly, the fast moving car has a greater velocity and thus more momentum than the slow moving car.
Momentum is defined as the mass of an object multiplied by its velocity. That is:
Momentum = mass x velocity
Or in shorthand notation,
Momentum = mv
We can see from the definition that a moving object can have a large momentum if either its mass is large, or its speed is large, or both. A truck has a larger momentum than a car moving at the same speed because its mass is larger. A weighty ship moving at a small speed and a lightweight bullet moving at high speed can both have the same large momentum. And, of course, a heavy object moving at a high speed, such as a massive truck rolling down a steep hill with no brakes, has a huge momentum. The same truck at rest has no momentum at all.
Momentum is Conserved
When a moving object hits another object, some or all of the momentum of the first object is transferred to the other object. If only some of the momentum is transferred, the rest of the momentum stays with the first object.
Imagine you hit a billiard ball with a cue ball so that the billiard ball starts moving and the cue ball stops. The cue ball had a certain amount of momentum before the collision. During the collision, all of the cue ball’s momentum was transferred to the billiard ball. After the collision, the billiard ball moved away with the same amount of momentum the cue ball had. This example illustrates the law of conservation of momentum. Any time two or more objects interact, they may exchange momentum, but the total amount of momentum stays the same.
Bowling is another example of how conservation of momentum is used in a game. The bowling ball rolls down the lane with a certain amount of momentum. When the ball hits the pins, some of the ball’s momentum is transferred to the pins and the pins move off in different directions. Furthermore, some of the pins that were hit by the ball go on to hit other pins, transferring the momentum again.
Conservation of Momentum and Newton’s Third Law
Conservation of momentum can be explained by Newton’s third law. In the example with the billiard ball, the cue ball hit the billiard ball with a certain amount of force. This was the action force. The reaction force was the equal but opposite force exerted by the billiard ball on the cue ball. The action force made the billiard ball start moving, and the reaction force made the cue ball stop moving. Because the action and reaction forces are equal and opposite, momentum is conserved.
Click on the following link to answer the Momentum questions
Momentum Questions
