9.1- MOMENTUM AND IMPULSE Flashcards
When two bodies collide, what does the effect they have on each other depend on? (2)
their initial velocities + mass of each object
What did Sir Isaac Newton realise about force in relation to velocity?
force needed to change velocity of object
What did Newton define momentum of a moving object as?
mass * its velocity
What law is used to carefully launch a rocket?
Newton’s law of motion + his law of gravitation
What is the momentum of an object defined as?
its mass * its velocity
What is the unit of momentum?
kg ms^-1
Is momentum a vector or scalar quantity?
vector
What is the direction of momentum the same as?
direction of object’s velocity
What is Newton’s first law of motion?
object remains at rest or in uniform motion unless acted on by force
What does Newton’s first law tell us?
force needed to change momentum of object
What is the resultant force like if the momentum of an object is constant?
no resultant force acting on it
What follows if mass of object constant + object has constant momentum?
velocity of object also constant
If a moving object with constant momentum gains/loses mass, what must the velocity be like?
its velocity would change to keep its momentum constant
What is Newton’s second law of motion?
rate of change of momentum of object proportional to resultant force on it
resultant force proportional to change of momentum per seconds
What can Newton’s second law of motion be written as? (equation)
force = mass * acceleration
What is the equation for force when an object of constant mass m is acted on by a constant force F?
F = m(v - u) / t = ma
F = Δ(mv) / Δt
If the mass m changes at a constant rate, what is the equation for force F?
F = vΔm / Δt
What is the impulse of a force defined as?
force * time for which force acts
What is the equation for impulse?
impulse = FΔt = Δ(mv)
What is the impulse of a force acting on an object equal to?
change of momentum of object
What does the area under the line of a force-time graph represent?
change of momentum or impulse of force
What can the unit of momentum be given as?
Ns or kg ms^-1
What is the unit of impulse usually given as?
Ns
