Science Topic 3 Lessons 1 & 2

Content for Lessons 1 & 2

Motion

An object is in motion if its position changes when compared to another object.

Reference Point

A place or object used to determine whether something is in motion.

Relative Motion

Motion that is determined by a reference point that can change.

Force

A push or pull on an object described by its strength and direction.

Contact Forces

Forces that are applied only when one object touches another.

Noncontact Forces

Forces applied to an object whether it touches the object or not.

Net Force

The combination of all the forces acting on an object.

Balanced Forces

Forces that result in a net force of zero.

Unbalanced Forces

Forces that result in a non-zero net force acting on an object.

Speed

The distance an object moves per unit of time.

Instantaneous Speed

The speed of an object at a particular instant in time.

Average Speed

The total distance traveled divided by the total time.

Velocity

The speed of an object in a given direction.

Acceleration

The rate at which velocity changes.

Change in Velocity

Can involve a change in speed, direction, or both.

Constant Speed

An object that travels at the same speed but can still accelerate if it changes direction.

Rate

The amount of something that occurs during changes in one unit of time.

Direction

The line along which something moves or faces, needed to describe motion.

Instantaneous Speed Calculation

To calculate, divide the distance traveled by the time taken.

Average Speed Calculation

To calculate, divide the total distance traveled by the total time.

Force Classification

Forces can be classified as contact or noncontact forces.

Unbalanced Forces Effect

Cause an object to accelerate or change its motion.

Net Force Calculation

If forces act in the same direction, the net force is the sum; if opposite, the difference.

Acceleration Definition

Refers to any change in speed or direction.

Effects of Forces

An object's motion can change when one or more forces act on it.

Example of Contact Force

Friction, tension, and normal force are types of contact forces.

Example of Noncontact Force

Gravity and magnetic forces are examples of noncontact forces.