7th Grade Science - Physical Science

Newton's First Law of Motion

An object at rest will remain at rest, and an object in motion will remain in motion unless acted upon by an unbalanced force. This principle is known as the Law of Inertia.

Gravity

A force that attracts two bodies toward each other, proportional to their masses and inversely proportional to the square of the distance between them.

Friction

A force that opposes the motion of an object, resulting from the contact between two surfaces.

Push and Pull Forces

Forces exerted by either pushing or pulling that cause an object to move or change its velocity.

Newton's Second Law of Motion

The acceleration of an object depends on the mass of the object and the amount of force applied, expressed as $F=ma$.

Relation between Force, Mass, and Acceleration

According to Newton's second law, increasing the force on an object increases its acceleration, while increasing the mass decreases its acceleration if the force remains constant.

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction.

Action and Reaction Forces

In any interaction, the forces exerted by two objects on each other are equal in magnitude and opposite in direction.

Device Constructed with Newton's Laws

An example of these principles in action can be seen in devices such as a rocket, which uses Newton's third law by expelling gas (action) and moving in the opposite direction (reaction).

Inertia

The tendency of an object to resist changes in its state of motion.

Acceleration

The rate of change of velocity of an object with respect to time.

Velocity

The speed of an object in a given direction.