06 - further mechanics Flashcards
What is impulse?
Impulse is equal to the change of momentum.
State the equation used to calculate the impulse of a force acting over a time.
Impulse = F Δt
If there a fixed change of momentum that must occur, how do you reduce the force that is exerted in the process?
Increase the length of time over which the change of momentum occurs.
What is the conservation of linear momentum?
The total momentum before an event must be equal to the total momentum after an event, assuming no external forces act.
State the conservation of linear momentum in equation form.
M1V1 =M2V2
What is an elastic collision?
A collision in which kinetic energy is conserved.
Is energy conserved in an inelastic collision?
Yes - energy is always conserved.
However, kinetic energy is not conserved in an inelastic collision - the energy is instead converted to other forms.
State the equation used to calculate angular velocity.
ω = v/r
v is the linear velocity
r is the radius of the circular path
What is the time period of a circular orbit with angular velocity ω?
T = 2π/ ω
What is required for an object to move with circular motion?
A centripetal force.
In what direction does a centripetal force act?
Perpendicular to the direction of the object’s motion, towards the centre of the circular path.
What equation is used to calculate a centripetal force?
F = mv^2/r = mr ω^2
What is the equation for the kinetic energy of a non-relativistic particle?
E = p^2 / 2m
what does area under a force time graph represent
change in momentum
difference between time period and frequerncy?
the time period is the time for one rotation, frequency is how many rotations per second
