AP Physics WORK AND ENERGY

Work

The process or moving an object by appkying a force

W = FD

MOST BASIC equation for work

J, Nm, kgm^2/s^2

3 ways to write units for work

W = FDcosø

Equation for work when the force is at an angle

Work

Represented by area under Force vs Displacement Graph

Power

The rate at which work is done

P = W/t

Equation for Power

W, J/s, Nm/s, kgm^2/s^3

4 ways to write units for power

P = Fv

Alternative equation for power

Energy

The ability or capacity to do work, or the ability or capacity to move an object, can be transformed from one kind to another

Chemical, elastic, gravitational, nuclear, electrical

5 examples of potential energy

Electrical, thermal, light, sound, wind

5 examples of kinetic energy

Work-Energy Theorem

The work done on a system by an external force changes the energy of the system, if the external force is positive, the energy of the system increases. If the system does work, the system's total energy decreases

W = 🔺Etotal = FDcosø

Equation for the work-energy theorem about change in energy

J, Nm, kgm^2/s^2

3 ways to write units for energy

Kinetic energy

Energy of motion, the ability or capacity of a moving object to move another object

K = 1/2mv^2

Equation for Kinetic Energy

Potential Energy

Energy an object possesses due to its position or condition

Gravitational potential energy

The energy an object possesses because of this position in a gravitational field (height)

Ug = mgh

Equation for Gravitational Potential Energy

Inverse

Relationship between kinetic and potential energy

Hooke's Laws

The more you stretch or compress a string, the greater the force of the spring

Fs = -kx

Equation for the linear relationship of Hooke's Law

Spring Constant

Represented by slope of the Force vs Displacement Graph

k = F/x

Equation for spring constant

Elastic Potential Energy

The work done in compressing a spring

Us = 1/2kx^2

Equation for elastic potential energy

Internal energy

Work done by an object against friction

v = <2K/m>

Equation for velocity using Kinetic Energy equation

P = 🔺E/t

Equation for power involving energy

W = (1/2mv^2) - (1/2mvo^2)

Equation for net work involving mass and velocity

Law of Conservation of Energy

Energy cannot be crated or destroyed, only changed

Total/Mechanical Energy = K + Ug + Us

Equation for Conservation

v =

Equation for velocity in conservation of energy problems involving K and Ug

K = Et - Ug

Example of an equation created by considering conservation of energy, serves to solve for kinetic energy in a problem also involving gravitational energy

k = 2K/x^2

Equation relating spring constant and Kinetic Energy

Inverse

Relationship between kinetic energy and work done by friction