Remember Newton's First Law? It said that any object moving will continue moving unless it is interfered with. That idea applies to momentum as well. The momentum of an object will never change if it is left alone. If the 'm' value and the 'v' value remain the same, the momentum value will be constant.
The momentum of an object, or set of objects system , remains the same if it is left alone. Within such a system, momentum is said to be conserved. Here's the momentum idea in simpler terms. When you throw a ball at someone and it hits him hard, it hurts because it was difficult to stop had momentum.
Think about it. If you throw a small ball and a large ball at the same speeds, the large ball will hit a person with a greater momentum, be harder to stop, and hurt more. When the mass is greater at the same speeds , the momentum is greater. A bullet is an example of an object with a very small mass that has a lot of momentum because it is moving very quickly. Bullets are therefore difficult to stop; it's a good idea not to try! FALSE - Two colliding objects will only experience the same velocity change if they have the same mass and the collision occurs in an isolated system.
However, their momentum changes will be equal if the system is isolated from external forces. It is momentum which is conserved by an isolated system of two or more objects.
TRUE - Two colliding objects will exert equal forces upon each other. If the objects have different masses, then these equal forces will produce different accelerations. FALSE - It the colliding objects have different masses, the equal force which they exert upon each other will lead to different acceleration values for the two objects. FALSE - Total momentum is conserved only if the collision can be considered isolated from the influence of net external forces. FALSE - In any collision, the colliding objects exert equal and opposite forces upon each other as the result of the collision interaction.
There are no exceptions to this rule. FALSE - In any collision, the colliding objects will experience equal and opposite momentum changes, provided that the collision occurs in an isolated system. TRUE - A perfectly elastic collision is a collision in which the total kinetic energy of the system of colliding objects is conserved. Such collisions are typically characterized by bouncing or repelling from a distance.
In a perfectly inelastic collision as it is sometimes called , the two colliding objects stick together and move as a single unit after the collision. Such collisions are characterized by large losses in the kinetic energy of the system. A completely elastic collision occurs only when the collision force is a non-contact force.
Most collisions are either perfectly inelastic or partially inelastic. FALSE - Momentum can be conserved in both elastic and inelastic collisions provided that the system of colliding objects is isolated from the influence of net external forces.
It is kinetic energy that is conserved in a perfectly elastic collision. It is the system of colliding objects which conserves kinetic energy. TRUE - Kinetic energy is lost from a system of colliding objects because the collision transforms kinetic energy into other forms of energy - sound, heat and light energy. When the colliding objects don't really collide in the usual sense that is when the collision force is a non-contact force , the system of colliding objects does not lose its kinetic energy.
Sound is only produced when atoms of one object make contact with atoms of another object. And objects only warm up converting mechanical energy into thermal energy when their surfaces meet and atoms at those surfaces are set into vibrational motion or some kind of motion.
TRUE - If large amounts of kinetic energy are conserved when a ball collides with the ground, then the post-collision velocity is high compared to the pre-collision velocity. The ball will thus rise to a height which is nearer to its initial height. Before the collision, all the kinetic energy is in the first glider.
After the collision, the first glider has no kinetic energy; yet the second glider has the same mass and velocity as the first glider. As such, the second glider has the kinetic energy which the first glider once had. TRUE - There is significant bounce in the collision between a tennis racket and tennis ball. There is typically little bounce in the collision between a halfback and a linebacker though there are certainly exceptions to this one.
No information is given regarding direction, and so we can calculate only the magnitude of the momentum, p. As usual, a symbol that is in italics is a magnitude, whereas one that is italicized, boldfaced, and has an arrow is a vector. Although the ball has greater velocity, the player has a much greater mass.
Thus the momentum of the player is much greater than the momentum of the football, as you might guess. We shall quantify what happens in such collisions in terms of momentum in later sections. The importance of momentum, unlike the importance of energy, was recognized early in the development of classical physics. Using symbols, this law is. The net external force equals the change in momentum of a system divided by the time over which it changes.
Force and momentum are intimately related. Momentum continues to be a key concept in the study of atomic and subatomic particles in quantum mechanics. We can derive this form as follows. We will consider systems with varying mass in some detail; however, the relationship between momentum and force remains useful when mass is constant, such as in the following example.
What is the average force exerted on the 0. This problem involves only one dimension because the ball starts from having no horizontal velocity component before impact.
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