Chapter 4: Motion and Forces

This set of flashcards covers key vocabulary terms and definitions related to motion and forces as described in Chapter 4 of the Science Explorer Grade 7 textbook.

Force

A push or a pull acting on an object.

Net Force

The overall force on an object after all forces are added together.

Inertia

The tendency of an object to resist change in its motion.

Newton's First Law of Motion

An object at rest will remain at rest, and an object in motion will continue in motion at constant velocity unless acted upon by an unbalanced force.

Friction

The force that one surface exerts on another when the two rub against each other.

Gravity

The force that pulls objects toward Earth.

Momentum

The product of an object's mass and velocity.

Acceleration

The rate of change of velocity of an object.

Bernoulli's Principle

The principle stating that an increase in the speed of a fluid occurs simultaneously with a decrease in pressure.

Balanced Forces

Equal forces acting on one object in opposite directions.

Unbalanced Forces

Forces that cause a change in the motion of an object.

Mass

The amount of matter in an object.

Pressure

The force exerted on a surface divided by the total area over which the force is exerted.

Newton's Second Law of Motion

The net force acting on an object is equal to the product of its mass and acceleration.

Terminal Velocity

The constant speed an object eventually reaches when the resistance of the medium prevents further acceleration.

Fluid

A substance that can flow easily.

Projectile

An object that is thrown.

Air Resistance

A type of fluid friction that acts against the motion of an object moving through air.

Hydraulic System

A system that uses incompressible fluid to transmit force.