AP Physics I: Motion In One Dimension
Speed
(v) a scalar cannot be negative; how fast an object moves
Velocity
(v) the rate of change of position. Velocity is a vector.
Average Velocity Formula
(vi+vf)/(2); can use only if it changes at a constant rate or the equation can be d/t. D can represent displacement or distance. T represents time.
Slowing down in the negative direction
*Second Part of Graph
Step three in approaching acceleration motion problems
Create a table with the five motion problems Vi, Vf, a, d, and t
Kinematic Equation For Distance/Displacement (2)
D(X)= 1/2(Vi + Vf)t D(X)= Vi(t) +1/2(a)t^2
Step two in approaching acceleration motion problems
Define the diagram
Step one in approaching acceleration motion problems
Diagram the problem
Step four in approaching acceleration motion problems
Fill in table with known information. Must know three of the five variables to begin solving
Types of Velocity/Speed
Initial Velocity, Final Velocity, and the Change in Velocity
Describe the slope of a curve
It is different at each point on the curve. The slope of the tangent line is the slope of the curve at that point
Velocity-Time Graph
Must consist of line segments for constant acceleration
Step eight in approaching acceleration motion problems
Question if the answer is reasonable
Step five in approaching acceleration motion problems
Select an equation that has three known variables that is wanted
Step seven in approaching acceleration motion problems
Solve the problem
Step six in approaching acceleration motion problems
Substitute. Make sure to check units at this point
Example of Scalar
Time, Length, Area, Speed , Mass, Density, Temperature, Pressure, and Energy
Kinematic Equation For Final Velocity (2)
Vf= Vi + at Vf^2= Vi^2 + 2ad
Which variables do you assign direction to?
Vi, Vf, a, and d(x) -Do not assign direction to time
Acceleration Formula
a = change in velocity/time
Displacement
a straight line distance from the start to the finish without regard to where it went in between
Distance
a straight line distance with regard to where the object went in between; total length traveled
What is the slope of the velocity-time graph represent?
acceleration
How do you find the slopes of curves?
by drawing a tangent line and then finding the slope of the tangent line
Displacement equation
d=vt (Only at constant speed, which is when acceleration is 0) d=vagt xf-xi
In a velocity-time graph, the area under a velocity time graph represents the
displacement
What are the three types of motion graphs?
displacement vs time, velocity vs time, and acceleration vs time
Examples of Vector
displacement, acceleration, velocity, force; increase and direction in temperature
In the equation v=d/t, if d represents (blank), then v is equal to (blank)
displacement; velocity
In the equation v=d/t, if d represents (blank), then v is equal to (blank)
distance; speed
If velocity is constant that means acceleration is
equal to 0
Displacement vs Time
for constant acceleration, this graph is the only graph that can be a curve. It will be a curve when acceleration is not equal to 0. If acceleration is 0, it is a line.
Acceleration vs Time Graph
for constant acceleration, this graph must be a horizontal line segment
Magnitude
has a number and unit
One Dimension Motion
movement along a line, in one direction or the opposite direction, or both
If the area bounded by the graph is is below the y=0 it represents
negative displacement
The Displacement vs Time graph, is also called the
position vs time graph
If the area bounded by the graph is above the zero y value it represents
positive displacement
Vector
quantities that have both magnitude and direction
Scalar
quantities that have magnitude only; no direction
If the velocity and acceleration are in opposite direction, then the object will
slow down
If the velocity and acceleration are in the same direction, the object will
speed up
Speed is equal to
the absolute value of velocity
Acceleration
the rate of change in velocity over time
How do you represent direction?
use positive and negative signs
In a velocity-time graph, the area bounded by the graph and the 0 y-value is
v times t
Acceleration is a
vector
What does the slope of a distance vs time graph represent?
velocity
Instantaneous Velocity
velocity at a particular instant. Same as the final velocity at the instant
Change in Velocity is equal to
vf-vi
Velocity Average
vi+vf/2