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