7 - Laws of motion and momentum Flashcards
What is Newton’s first law?
An object will remain in the same state of motion if it has no force or two equal forces acting upon it, unless an additional force acts on it.
A stationery object remains at rest and a moving object remains at the same velocity.
What is Newton’s third law?
When two objects interact, they exert equal and opposite forces on each other; every action has an equal and opposite reaction.
What type of force is the force of two objects touching?
Contact force; due to electrostatic force.
repulsion of electrons in the atoms
What is the principle of the conservation of momentum?
For a closed system, the momentum in a certain direction remains constant.
Momentum before the collision = momentum after the collision
What is momentum?
The product of an objects mass and velocity; the tendency of an object to keep moving in the same direction.
What happens in a perfectly elastic collision?
- Momentum is conserved
- Kinetic Energy is conserved; no kenatic energy is tranferred into another form of energy.
What happens in an inelastic collision?
- Momentum is conserved
- Kinetic Energy is NOT conserved; some kinetic energy is transferred into another form of energy.
What is Newton’s second law?
The net force acting on an object is directly proportional to the rate of change of momentum and is in the same direction.
Why is momentum conserved, according to Newton’s laws?
3rd Law - interacting objects exert equal and opposite forces on each other (F, -F)
In contact for same amount of time
2nd Law - F = p/t -> p=Ft
Ft = -Ft
What is impulse?
A change in momentum
How is impulse represented on a force time graph?
The area under the graph
