Topic 3: dynamics Flashcards
What is Newton’s first law?
an object continues at constant velocity unless a resultant force acts on it
What is Newton’s second law?
The acceleration of a body is directly proportional to the resultant force that acts on it.
What is Newton’s third law?
If body A exerts a force on body B, body B will exert an equal but opposite force on body A.
What is momentum?
mass x velocity
How are resultant force and momentum related?
resultant force = rate of change of momentum
What is the equation relating resultant force and momentum?
F = (mv - mu) / t
What is impulse?
Change of momentum
What is the law of conservation of momentum?
total momentum before collision = total momentum after collision
What is the difference between elastic and inelastic collisions?
In an elastic collision, kinetic energy is conserved.
In an inelastic collision, kinetic energy is not conserved.
What is the rule about relative speed in ELASTIC collisions ONLY?
relative speed of approach = relative speed of separation
How do you find relative speed?
opposite directions = add
same direction = subtract
What equation relates momentum and kinetic energy?
Ek = p^2 / 2m
