Unit 1- Rotational motion Flashcards
(24 cards)
What is the definition of inertia?
The resistance to motion(Angular acceleration).
Deriving displacement gives you?
Velocity.
Deriving Velocity gives you?
Acceleration.
Integrating acceleration gives you?
Velocity.
Integrating velocity gives you?
Displacement.
Can we change the equations of motion from linear physics and apply them to rotational problems?
Yes, we just input the angular values for each.
How can you work out W (Omega)?
2π/T (Period or time) , 2πf
How can you work out angular displacement?
2π
in 1 rev the distance travelled is?
2πR
a machine rotates at 3000 rpm, whats the angular velocity?
3000x2π/60= 314.2 rads^-1
how do you get linear to tangential velocity?
v=W(omega)xR
what is centripetal acceleration?
if an object is travelling in a circle there is a force pulling it out of its natural linear motion and into a circular one, this force is an inward seeking force causing the object to have an inward acceleration.
if a ball is swung horizontally whats the equation for centripetal force?
Fcp= mv^2/r=T
if a ball is swung vertically whats the equation for centripetal force?
TOP- Fcp=mv^2/r = T+W
Bottom- Fcp=mv^2/r = T-W
If a car goes over a bridge whats the equation for Centripetal force? what happens to the reaction force when the car leaves the ground?
Fcp=mv^2/r=W-R, the reaction force would be 0 if car lifts off the ground.
what is a torque?
Tangential force x Radius(Distance) from the axis of rotation, if the force is applied at and angle then the equation is multiplied by sin(Angle)
is angular momentum always conserved in the absence of external forces?
yes, however kinetic energy isn’t always.
whats can we say about the force between masses?
They’re always attractive.
what is the moment of inertia?
The measure of how difficult it is to change the motion of a rotating body.
what is gravitational potential measured from?
Gravitational potential is measured from infinity to 0
what 2 equations derive the period for satellites?
Mv^2/r = GM1M2/r^2 (knowing that: v=Wr and w=2π/T)
whats the difference between special and general relativity?
special = objects moving with a constant speed, general = objects which are accelerating.
what is the equivalence principle?
There is no way to distinguish the effect on an observer of being accelerated or being in a uniform gravitational field.
why is weight not a real thing?
as it can be the same ass accelerating at 9.8 ms^-2
