3.5 - Momentum Flashcards
Newton’s First Law
An object will remain at rest or continue to travel with constant velocity unless acted upon by a resultant force.
Newton’s Third Law
When two objects interact, they exert equal and opposite forces on each other.
Newton’s Second Law
The net force acting on an object is directly proportional to the rate of change of momentum.
Example of Third Law
Gravitational attraction of the earth to a person standing on it.
Four fundamental forces
Gravitational, electromagnetic, strong nuclear, weak nuclear
Define linear momentum of an object
Product of the object’s mass and its velocity
p = mv
Why do we use impulse?
Forces acting on a body may vary over time. Impulse lets us analyse this motion.
What is impulse a measure of?
Change in momentum.
Define the impulse of a force.
The product of the force and the time for which it acts.
impulse = Δp = F x Δt = m(v-u)
What is the area under a force-time graph equal to?
The impulse over that time duration, which is also the change in momentum.
State the principal of conservation of momentum.
The total momentum of a system before an event must equal to the total momentum of a system after an event.
What two quantities are conserved in a perfectly elastic collision?
Kinetic energy and momentum.
What is conserved in an inelastic collision?
Momentum.
What happens to the kinetic energy in an inelastic collision?
It is lost to other forms such as heat and sound.
What is conserved for both elastic and inelastic collisions.
Total energy and momentum.
