Kinematics in One Dimension

The kinematic equation are only true if…

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