Unit 5: Applied Flashcards
What is a rotating system
When an object is spinning on its axis
What is meant by the term angular velocity
The angle an object passes through per second
What is the most commonly used way of expressing rate of turning
Revolutions per minute
How does one convert rpm to radians per second
2pi(rpm/60) = angular velocity
What is meant by angular displacement
The angle turned in a given direction.
What is the equation linking angular velocity and displacement
omega = theta/t
where omega = angular velocity, theta = angular displacement, t = time
What is the equation linking acceleration (angular) and angular velocity
alpha = deltaTheta/deltat
where alpha = angular acceleration
What is meant by moment of inertia
MoI is the measure of the opposition of a rotating body to angular acceleration
What are the units for moment of inertia
kgm^2
What is the equation for inertia
I=sigma*mr^2
I = inertia, m = mass, r = distance from centre of point
How does one derive the moment of inertia equation
- Know that a spinning body is made of point masses
- Using Ke = 0.5mv^2, the total kinetic energy can be found by taking the sum of the point massesthe distance from centre^2 all times angular velocity
- Simplyfy
What is the equation for the kinetic energy of a spinning object
Ek = (I*omega^2)/2
Where Ek = kinetic energy, I = Inertia, omega = angular velocity
What are the equations of rotational motion
Same as suvat replacing u, v and a with omega 1,2 and alpha
What is Torque
Any turning force
What is the equation for torque in relation to force
T = Fr T = force, F = force, r = radius
What are the rotational motion versions of:
- Displacement
- Velocity
- Acceleration
- Mass
- Force
- Angular displacement
- Angular velocipede
- Angular acceleration
- Moment of inertia
- Torque
How does one calculate torque taking into account the shape of the pulley, and explain how it takes this into account
T = I*alpha
Using inertia to take account for how the mass of the pulley is distributed
How does one calculate angular momentum
L = I*omega L= angular momentum, I = inertia, omega = angular velocity
What are the units for angular momentum
kgm^2s^-1
What is meant by the conservation of angular momentum
before = momentum after
provided there is no angular impulse
What is the equation for angular impulse
(deltaL) = T(delta*t)
What equation is used to calculate work done by a rotating system
W = T*theta
Equation for power in a rotational system?
P=T*omega
How is “angular” friction treated
as an opposing rotational couple which provides a torque in the opposite direction using T = I*alpha
