Momentum is a vector, so it may be zero to begin with. For example two objects with same mass, one moving at v and the other at -v. If they collide and stick together then the KE reduces to zero whereas the momentum was always zero.physea said:
Dale said:
It is not an exceptional situation. Any collision can be analyzed in the center of momentum frame. It is one of the most common strategies for solving collision problems in particle physics.physea said:
physea said:
Why must the friction be with a body outside the system?PeroK said:
A.T. said:
Where did the momentum go?physea said:
Think about a collision between two identical objects that stick together, one starting stationary. The final speed is half the initial speed of the first object, momentum is conserved and energy is lost. The math to demonstrate this is straightforward...physea said:
Internal forces can transform energy form one form to another, but cannot change momentum.physea said:
Work out the numbers. You will see, only KE is lost, not momentum.physea said:
physea said:
Momentum conservation is a fundamental principle in physics that states that the total momentum of a closed system remains constant in both magnitude and direction, unless acted upon by an external force. In simpler terms, it means that the total amount of motion in a system remains the same unless an external force is applied.
Momentum and kinetic energy are closely related, as both are measures of motion. However, while momentum measures the quantity of motion, kinetic energy measures the quantity of motion and the mass of the object. In other words, momentum is the product of an object's mass and velocity, while kinetic energy is the product of half the mass and the square of the velocity.
Momentum conservation can be observed in many everyday situations. For example, when a car collides with another car, the total momentum of the system remains the same before and after the collision, even though the individual momentums of the two cars may change. This also applies to sports, such as when a baseball player catches a ball, the momentum of the ball is transferred to the player's body.
Understanding momentum conservation is crucial in analyzing the effects of collisions. In a perfectly elastic collision, where no energy is lost, the total momentum of the system remains the same before and after the collision. However, in an inelastic collision, where some energy is lost in the form of heat or sound, the total momentum of the system may change due to the external forces acting on the objects.
Newton's third law of motion states that for every action, there is an equal and opposite reaction. This is closely related to momentum conservation, as when two objects collide, the force exerted on each other is equal and opposite, therefore their momentums must also be equal and opposite. This principle is also applicable in many other scenarios, such as when a rocket is launched into space, the force exerted by the exhaust gases on the rocket is equal and opposite to the force propelling the rocket forward.
