Newton's Laws and Net Forces

Peaks, Fall 2021

Net force

The sum of all forces acting on an object

Balanced Forces

Equal forces acting on an object in opposite directions

Balanced forces acting on an object

do not change the object's motion

Unbalanced Forces

Forces acting on an object that combine and form a net force that is not zero

Unbalanced forces acting on an object

result in a net force and cause a change in the object's motion

Newton's First Law (Law of Inertia)

An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

Inertia

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

What determines the inertia of an object?

Mass (Greater mass, greater inertia)

An object with a small mass has \____________________ inertia than an object with a large mass.

Less inertia

Newton's Second Law (Law of Acceleration)

A force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body's mass.

Newton's second law equation

Force \= Mass x Acceleration (F\=ma)

Acceleration

Change in velocity divided by the time it takes for the change to occur (rate of change of velocity)

An object with a small mass has \____________________ acceleration than an object with a larger mass.

(Same for gravity, less for everything else)

F\=ma Units of measurement for

F\=Force (newtons), M\=Mass (kilograms), A\=Acceleration (m/s^2, or meters per second per second)

Newton's Third Law of Motion (The law if action and reaction)

For every action there is an equal and opposite reaction

Newton's Third Law of Motion is also knows as \__________________

The law of action and reaction

Forces must always occur in \_____________

pairs

A bat hitting a baseball (list the reaction force)

The baseball hitting the bat