# Reg Science Test Motion

## 34 terms · HIES 8th Grade Jackson Motion Test

### Force

A push or a pull on objects

Newton

### Balanced Force

equal forces on an object that cancel out; no net force

### Unbalanced Force

unequal forces on an object; you get a net force; causes the object to accelerate

### Motion

a change in position

### What do you need to see motion?

a reference point

how far you go

### Displacement

distance between starting and ending point

how fast you go

### Speed Formula

distance divided by time

### Velocity

speed with a direction

### What changes velocity?

speed or direction

### Acceleration

changing velocity over time

### Acceleration Formula

(final velocity-original velocity) divided by time

### 3 Things That Affect Acceleration

speeding up, slowing down, changing direction

### Inertia

resistance to motion

### What affects Inertia?

mass of an object; the larger the mass the greater the inertia

Law of Inertia

### What does the First Law of Motion say?

An object at rest or motion will stay that way unless an outside force (net force)

### What does the Second Law of Motion show?

it shows how force, mass and acceleration are related

### What does the Second Law of Motion say?

a net force on an object causes it to accelerate in the direction of the force

### Second Law of Motion formula

mass times acceleration

Reaction Law

### What does the Third Law of Motion say?

for every action force there is an equal and opposite reaction force

### Friction

resistant force caused when two surfaces touch

### What affects friction?

type of surface and mass of an object; NOT the amount of surface touching

### 3 Types of Friction

Static, Sliding, Rolling

### Static Friction

the greatest kind of friction; keeps the objects at rest

### Sliding Friction

less than static; when objects start to move

### Rolling Friction

least kind of friction; occurs with wheels and rollers

### 3 Ways to Decrease Friction

Lubrication, Wheels and Rollers, Sanding and Polishing

### Momentum

inertia in motion

### What is momentum affected by?

mass and velocity

### Momentum Formula

mass times velocity