The kinematic equation are only true if…
acceleration is constant
When an object switches directions by decelerating enough, it then…
speeds up
vf =
vi + a∆t
∆x =
vi∆t + ½a(∆t)²
∆x =
(no acceleration)
(vf + vi/2)∆t
vf² =
vi² + 2a∆x
Acceleration of gravity
-9.81 m/s² or 9.81 down
The slope of a position-time graph is the _______
velocity
The slope of a velocity-time graph is the _________
acceleration
Vectors
Magnitude and direction (velocity, position, displacement, acceleration)
Scalars
Magnitude (speed, mass, time, distance)
Displacement
how far from your starting point and direction
If you are moving in a circle at a constant speed, your velocity is…
changing and you are accelerating because you’re changing direction
a =
∆v / ∆t
v =
∆x / ∆t
In horizontal problems, right is ____ and left is ________
positive; negative
In vertical problems, up is ____ and down is ______
positive; negative
At the top of an object’s path thrown up, the velocity is…
0
Motion is _________ about its peak
symmetric (same time going up as going down)
Acceleration is in the _______ direction as velocity if you are speeding up
same
Acceleration is the _________ direction as velocity if you are slowing down
opposite
The sign of acceleration or velocity indicates its…
direction (up/down or left/right)
Absolute value =
magnitude
Speed =
absolute value of velocity
For motion maps, dots that become closer indicate…
negative acceleration
For motion maps, dots that become farther indicate…
positive acceleration
For motion maps, dots that are evenly spread indicate…
constant velocity
Position-time graphs that flatten at the top indicate…
negative acceleration
Position-time graphs that curve upward indicate…
positive acceleration
Constant velocity =
0 acceleration
The sign of velocity depends on its…
direction
Velocity is positive if the object is moving to the right of the…
origin
Origin
point that defines which areas are positive and negative
An object to the right of the origin has a ________ position denoted by the y-axis
positive
If an object moving to the right of the origin is decelerating, the velocity is _______ (pos/neg) and the acceleration is ________ (pos/neg)
positive; negative
If an object moving to the right of the origin is accelerating, the velocity is _______ (pos/neg) and the acceleration is ________ (pos/neg)
positive; positive
Anything that drops or falls has an acceleration of…
-9.81 m/s²
When a position-time graph is flat, the velocity is…
0
Constant velocity motion
∆x = v∆t
An object going up ____, while an object going down _____
decelerates; accelerates