Physics 1: Key Concepts in Mechanics

Mass - Definition

The amount of matter in an object.

Mass - Units

Kilograms (Kg)

Position - Definition

An object's location relative to a reference point.

Position - Units

Meters (m)

Path Length

The total distance traveled along the path of motion.

Does not include direction.

Displacement

The change in an object's position from its initial starting point to its final resting point.

Includes distance and direction.

Time - Definition

A measurement of how long an event or motion lasts.

Time - Units

Seconds (s)

Speed - Definition

How fast something is moving. Speed is the distance traveled per unit time. Does not include direction.

Velocity - Definition

The rate of change of displacement.

Velocity describes how fast and in what direction something moves.

Speed and Velocity - Units

Meters per second (m/s)

Acceleration - Definition

The rate of change of velocity.

"Anything that will spill your coffee while driving."

Acceleration - Units

Meters per second per second OR Meters per second squared (m/s^2)

Force - Definition

A push or pull that can change an object's motion.

Force - Units

Newtons (N)

Equivalent to a kilogram meter per second squared ( kg m/ s^2 )

Net Force

The total force acting on an object after adding all forces together.

Work - Definition

Energy transferred when a force moves an object through a distance.

Occurs when force causes displacement.

Work - Units

Joules (J)

Equivalent to a Newton meter (N m)

Energy - Definition

The ability to do work.

Energy - Units

Joules (J)

Equivalent to a Newton meter (N m)

Power - Definition

The rate at which work is done or energy is transferred.

Power - Units

Watts (W)

Equivalent to Joules per second (J/s)

Kinetic Energy (KE)

Energy an object has because of its motion.

Potential Energy (PE)

Stored energy due to an object's position or configuration.

Potential Energy due to Gravity (PEg)

Energy an object has because of its height above the ground (or another reference level).

Potential Energy due to Spring force (PEs)

Energy stored in a spring when it is stretched or compressed.

Mechanical Energy (ME)

The total energy of motion and position in a system.

Conservative Force

A force that converts energy between forms but does not alter the total mechanical energy.

Nonconservative Force

A force that adds or removes mechanical energy from the system.

Newton's Second Law Equation

Newton's Second Law Equation in Equilibrium

Sigma F = 0

Work Equation

Kinetic Energy Equation

Gravitational Potential Energy Equation

Spring Potential Energy Equation

Work-Energy Theorem

Nonconservative Work Equation

Wnc = MEf - MEi

Momentum - Definition

the amount of motion an object has and its resistance to changing that motion

Momentum - Units

Newton seconds (Ns)

OR

Kilogram meters per second (kgm/s)

Impulse - Definition

A force applied over time that changes an object's momentum.

A change in momentum.

Impulse - Units

Newton seconds (Ns)

OR

Kilogram meters per second (kgm/s)

Angular Displacement (Δθ) - Definition

The change in an object's angular position as it rotates.

It measures how far something has rotated.

Angular Displacement (Δθ) - Units

Radians (rad), revolutions (rev), or degrees

Angular Velocity (ω) - Definition

The rate at which angular displacement changes.

How fast something rotates.

Angular Velocity (ω) - Units

Radians per second (rad/s) or Revolutions per minute (rpm)

Angular Acceleration (α) - Definition

The rate at which angular velocity changes.

How quickly rotation is speeding up, slowing down, or changing directions.

Angular Acceleration (α) - Units

Radians per second per second or radians per second squared (rad/s^2)