Kinematics
What is relative velocity?
How fast and in what direction an object is moving with respect to a given reference point.
What does Emech equal?
Kinetic + Potential Energy
What is impulse? Give two equations for it.
Impulse is the change in momentum! Either delta p or force * delta time. On a force vs. time curve, impulse is area under the curve.
Talk about Young's Modulus. In the stress part of the equation, what does A represent?
all material stretches :)
F/A = Y * delta L/L
What is momentum and when is it conserved?
It's a vector quantity equal to mass * velocity. It's conserved only when system is isolated.
How do we change between position, velocity, and acceleration graph? Draw an example
Derivatives!!!
brownian motion? kinetic theory? kinetic energy... and velocity? how do they relate to each other? and how does temperature come into play?
v = sqrt (3kbT/m)
What's the difference between static and kinetic friction? Give both equations.
Static = not moving, Fs <= mu*normal force
Fk = mu*normal force
What's density? How do you calculate it? Does the density of a liquid change throughout the liquid?
d = m/v. no.
you swing a yoyo on a string in a circle. draw force of gravity and force of tension at top and bottom. whats acceleration of yoyo?
at top both point down, at bottom, tension points up
How do you solve kinematics problems (Hint: FANCLAN, but describe all the steps!)
FANCLAN
When is work positive, negative, or 0?
+ when theta < 90
- when theta > 90
0 if theta = 90
(F dot D) = F*D*cos theta
What are viscous and pressure drag and what are their equations? When do we use each?
Viscous (small) = 6pi*eta*R*v
Pressure (big) = 1/2C*rho*A*v^2
Pascal! What's the law and what does it tell us about the pressure at the same heigh in a liquid.
Pf = Po + rho*g*h
equal!
What are the two right hand rules? When do we use them?
1) Torque (cross product)
2) angular velocity (omega)
what're the rotational kinematics equations?
.... latin -> Greek
KE = 1/2*I*omega^2. What's I and how do you calculate it?
moment of inertia = sum of m*r^2
Draw two vectors (R and F) and tell us where Torque is pointing.
:)
so Bernoulli? what's the equation?
P1 + 1/2rho*v^2 + rho*g*h = same thing but 2
omega = 2pi*f = 2pi/T
T = 2pi/omega
T = 1/f
omega = sqrt (k/m)
x(t) = Acos/sin (omega*t)
cannon (mass m1) moves towards edge of cliff at speed (velocity v1) and then fires A (mass m2) horizontally forward. As a result, canon comes to a stop at edge of cliff and A stops a distance d from the edge of cliff, which is heigh h above ground.
What's mass of cannon?
m2 * (d *sqrt (g/2h) - vi)/vi
check problem #3 from section 4 (mini exam) for full solution
Boltzmann Distribution is a lot, but you know it! What does it tell us about prob of being in state 2 vs. state 1.
e^(-deltaU/kbT)
archimedes principle! how many inches did the water in Tyler's bathtub rise? alternate question: in the equation, do we use density of fluid or object? do we use volume of fluid or object?
rho = fluid
volume = displaced (object)
what does Reynold's number help us determine? what's the equation?
if flow is laminar/turbulent (laminar < 2000, turbulent > 4000)
= rho*v*L/eta
volume flow rate + Venturi effect! what are they and what do they tell us?
volume flow rate (area and velocity) (Q1 = Q2), so smaller area = higher velocity
venturi (pressure and velocity), velocity increase, pressure decrease