| What is momentum | the product of a moving objects mass and velocity |
| what is the formula for momentum | p=mv
where p is momentum in kgms-1
m is mass in kg
v is velocity in ms'1 |
| what type of quantity is momentum? | vector |
| what is the law of conservation of momentum? | when two objects collide the total momentum before the collision is equal to the total momentum after the collision in the absence of external forces. |
| what is an inelastic collision | a collision in which kinetic energy is lost |
| what is an elastic collision? | a collision in which kinetic energy is conserved
(kinetic energy is the same before and after the collision) |
| what is the formula for kinetic energy? | ek=1/2mv^2
where ek is kinetic energy in joules
m is mass in kg
v is velocity in metres per second |
| what is an explosion | a collision where the momentum before and after is 0 |
| what is impulse | the change in momentum
(the product of average force and time of contact for a collision) |
| what is the formula for impulse | impulse = Ft
where impulse is measured in Newton seconds (Ns)
f is force in Netwons
t is time in seconds |
| what kind of graph is this | force time graph
often the force changes during a collision so calculations involve the average force |
| what is the area under a force time graph equal to | impulse |
| what happens when you increase time of contact for any collision with a fixed change in momentum? | the peak/average force is reduced |
| what formula do you use when doing calculations involving momentum of two objects | m1u1 + m2u2 = m1V1 + m2V2 |
| how can you figure out by experiment if a collision is elastic | record mass of each vehicle and speed of each vehicle before and after collision use ek=1/2mv^2 to calculate the total kinetic energy before and after the collision if kinetic eenrgy is the same before and after, the collision is elastic |
