Chapter 9 - Force and momentum Flashcards
What is momentum?
The momentum of an object is its mass multiplied by its velocity.
p = mv
A vector quantity that acts in the same direction as velocity.
The area under the line of a force-time graph represents the…
…change of momentum or the impulse of the force.
What is the equation of the change of momentum of a ball bouncing elastically off a wall?
-2mu
If the ball bounces perpendicular to the wall
-2mucosθ
What is Newton’s third law of motion?
When two objects interact, they exert equal and opposite forces on each other.
What is an elastic collision?
One where there is no loss of kinetic energy.
What is an inelastic collision?
One where the total kinetic energy after the collision is less than the total kinetic energy before the collision.
Some or all of the kinetic energy is transferred to other energy stores during the collision.
How is force related to momentum?
What is the equation?
The product of force and time for which a force acts (contact time). Change in momentum.
FΔt = Δ(mv) = Δp
What is the principle of conservation of momentum?
For an isolated system of objects with no external forces, the total momentum remains constant.
i.e.
Total initial momentum = Total final momentum
What are the equations of momentum?
p = mv
p = Ft
What is an explosion?
An event in which two objects fly apart after being initially at rest, they recoil from each other with equal and opposite amounts of momentum.
The higher the contact time in a collision, the _____ the impact force.
The higher the contact time in a collision, the lower the impact force.
What is Newton’s second law of motion?
Force is proportional to the rate of change of momentum.
F = P/t.
For constant mass, F = ma
