What Equation?
A ball starts at rest at a position of 0 m. It then accelerates for 2 seconds to a final position of 10 m. What was the acceleration of the ball?
Xf = x0+ v0t + 1/2at2
The Long Kinematics Equation!
What is the difference between Scalar and Vector quantities?
Scalar quantities tell you the magnitude.
Vector quantities tell you the magnitude AND direction
What does it mean when an object is in free fall?
Gravity is the only force acting on it?
What are the units for momentum?
kg x m/s
What are the units for frequency?
Herts (Hz)
A force of 16 N is applied to a ball for 2.4 seconds. What is the impulse of the ball?
p=mv
What 3 things should you check for when you are drawing a free body diagram?
Arrows pointing away
Length = Strength
Arrows are labeled
If I am looking at an acceleration-time graph, how would I find velocity?
*hint: would you go up or down the A-V-X ladder?*
Area
What are the steps to a change problem?
1. write OG equation
2. build your skeleton
3. replace variables (same or different)
4. multiply by change factor
What is the definition of frequency?
How many cycles are completed in 1 second
0.23 kg bullet travelling at 230 m/s penetrates a stationary 2 kg black of wood and emerges from the other side of the wood with a velocity of 270 m/s. How fast is the wood moving after the collision?
COLLISIONS EQUATION! P1+P2 = P1' + P2'
What three things are true for an object in equilibrium?
Acceleration = 0 m/s2
FNet = ON
Velocity is constant
When looking at our A-V-X ladder, what do we find when we are going UP the ladder?
SLOPE
What type of collision has the same Vo, different Vf, and the kinetic energy is NOT conserved?
Recoil interactions (explosions)
Why can an object in UCM never be in equilibrium?
It's velocity and acceleration are constantly changing because it is moving in a circle?
A test car moves at a constant speed around a circular track. If the car is 48.2 m from the track's center and has a centripetal acceleration of 8.05 m/s^2, what is the car's tangential velocity?
ac=vt2/r
DONT HAVE ENOUGH INFO FOR TANGENTIAL VELOCITY
What are the steps for an elevator problem?
1. Fg = mg (get Fdown)
2. a = Fnet/m (get FNet)
3. Fnet = Fup - Fdown
What is your vertical acceleration and horizontal acceleration for a projectile?
Vertical acceleration = -10 m/s2 ALWAYS
Horizontal acceleration = 0 m/s2 ALWAYS
What is the collision where the objects stick together with the SAME final velocity?
Totally Inelastic Collisions
What are the 3 ways to find the period of an object from a position time graph?
Mountains
Valleys
3 x-intercepts
Manny messed up Carlos' haircut, so Carlos decides to push him. Manny was standing, at rest, and after being pushed, he slid across the ground with an acceleration of 3 m/s^2 and crashed into the wall with a velocity of 11 m/s. How far did he slide?
vf2=v02+ 2a(xf - x0)
What does it mean when variables are directly proportional?
They have the same rates of change
What is the difference between static friction and kinetic friction?
Static friction is the friction acting on an object at rest
Kinetic friction is the friction acting on an object that is moving and sliding
If Ms. G kicks a 2 kg kickball that is initially at rest with a force of 42 N, how much force does the kickball exert on Ms. G
-42 N
(Newton's 3rd Law)
Ms. G owns a pink satellite that orbits around Venus. She adds some rhinestones to her satellite so that the mass to doubled, but it now orbits at the same distance from Venus.
How will the orbital velocity change?
It will stay the same
(mass of the satellite is IRRELEVANT)