# Physics Extra Credit

### By: Grace Graber

## Definitions

## Velocity

## Position

## Delta

## Acceleration

## Equations

## Acceleration

## Velocity

## Slope

## Pictures of the Equations

## Examples

## Example 1

If a car takes 20 seconds to travel from 20m to 84m, what the velocity of the car?

84 - 20 = 64m

64/20 = 3.2

V = 3.2 m/s## Example 2

If two cars are racing and Car A has 3 m/s and Car B has 4 m/s. How much time does it take for the cars to have acceleration of 8 m/s2?

8 = 4-3/t = 8 * t = 1/t * t

8t/8 = 1/8

t = 0.125s## Graphs

## Velocity vs. Time Graphs

## Calculating Displacement

## Velocity vs. time graphs of Accelerated Motion

## The Velocity vs. Time Graph

If an object is accelerating, it is easier to work with the velocity vs. time graph than it is to work with the position vs. time graph. The velocity vs. time graph is the best tool for understanding acceleration. It clearly shows how the velocity of an object changes with time.

## Constant Acceleration

*position*changes by the same amount each second. Constant acceleration means an object’s

*velocity*changes by the same amount each second.

## Calculating Acceleration

The slope of a velocity vs. time graph represents the acceleration of the object. Note that there is non-zero acceleration any time the velocity vs. time graph is *not perfectly horizontal.*

## Calculating acceleration from the Velocity vs. Time Graph

## Slope

The slope of a graph is equal to the ratio of *rise* to *run*. On the velocity vs. time graph, the rise and run have special meanings. The *rise *is the amount the *velocity *changes. The *run *is the amount the *time* changes.

## Acceleration and Slope

Acceleration is the change in velocity over the change in time. This is *exactly the same *as the rise over run for the velocity vs. time graph. The slope of the velocity vs. time graph is equal to its acceleration.

## Make a little Triangle to get the Slope

## Displacement on an Accelerated-Motion Graph

## Displacement

## Example

## Direction on Motion Graphs

## Newton’s First Law of Motion

## Force

A push, pull, or other action that has the ability to change motion.

## Forces, Mass, Inertia

## Newton's First Law

## Inertia

## Mass

## Units of Force

## Pounds

## Newton

## 1 Pound

## The Net Force

## Net Force

## Applications of Newton’s first law

- Seat belts and airbags
- Cup holders
- The tablecloth trick

## Newton's Second law

## Newton's Second Law

## Equation

Acceleration = Force/Mass

## Three Forms of the Second Law

*A = F/m - acceleration (a) - force (F) and mass (m)**F = ma - force(F) - mass (m) and acceleration (a)**M**= F/a - mass (m) - force (F) and acceleration (a)*