1.3 Flashcards
What is momentum?
the product of an object’s mass and velocity.
is a vector
Break down the equation p = mv
p = momentum (kgms^-1)
m = mass (kg)
v = velocity (ms^-1)
How does the momentum of two objects before a collision compare to the momentum of those two objects after a collision?
The total momentum before a collision is equal to the total momentum after the collision in the absence of external forces.
How do you calculate the momentum before the collision?
p1 = m1v1
p2 = m2v2
Describe an elastic collision
A collision in which there is no net loss of kinetic energy as a result of the collision.
Describe an inelastic collision
A collision in which there is a net loss of kinetic energy as a result of the collision.
What is an explosion?
a type of collision where the momentum prior to the collision is zero. As momentum is conserved, the momentum after the collision must also be zero.
What does a cannon move backwards after it fires a cannonball?
The cannon recoils to conserve the momentum of the explosion.
What is impulse?
The product of the force and the time the force is applied for during a collision.
Break down the equation impulse = Ft
Impulse (Ns)
F = average force (N)
t = time (s)
How do you calculate impulse on a force-time graph?
calculate the area under the graph
If momentum change stays constant, how does peak force of a collison change with duration of collision?
If you increase the duration of the collision, the peak force will decrease.
Find the velocity after the impact in a collision
m1v1 + m2v2 = (m1 + m2)v3
What happens if there is no air bag in the car during a collision?
- head hits a hard object
- in contact for a short time
- large force involved
- lots of damage
What happens if there is an air bag in the car during a collision?
- head hits air bag
- in contact for a longer time
- small force involved
- less damage
