Physics of Sports and Everyday Motion Reference Cheat Sheet

Key Facts

• Average speed is found with $v = \frac{d}{t}$, where $d$ is distance and $t$ is time.
• Acceleration measures change in velocity and is found with $a = \frac{\Delta v}{\Delta t}$.
• Newton's second law is $F_{\text{net}} = ma$, so a larger net force gives a larger acceleration for the same mass.
• Weight is the force of gravity on an object and is found with $F_g = mg$, where $g \approx 9.8\ \text{m/s}^2$ on Earth.
• Friction usually acts opposite the direction of motion, and more surface grip can help shoes, tires, and hands push effectively.
• Momentum is found with $p = mv$, so a faster or more massive object has more momentum.
• Kinetic energy is energy of motion and is found with $KE = \frac{1}{2}mv^2$.
• Power measures how quickly work is done and is found with $P = \frac{W}{t}$.

Vocabulary

Force

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

Net Force

The total force on an object after all forces are combined, which determines whether the object accelerates.

Friction

A contact force that resists motion between surfaces that touch.

Momentum

A measure of how hard it is to stop a moving object, calculated as mass times velocity.

Kinetic Energy

The energy an object has because it is moving.

Projectile

An object moving through the air after being launched, with gravity pulling it downward.