Energy
Table of Contents
Definition
- the capacity to do work.
- it is measured in Joules (J) similar to work.
- merely describes a property of system that can be transferred but cannot be created nor destroyed.
Work-Energy Theorem
Formula: \(W_{net} = \Delta KE\)
- when work is done \(W_{net}\) in an object, there will be a change in kinetic energy \(KE\).
- An object in motion can do work on another object.
Types
Kinetic Energy
- the energy while an object is in motion.
Potential Energy
- Energy that could be used to do work.
- Energy when the object is at rest.
- an example of this is gravitational potential energy.
- There is a relationship between force and potential energy, given the following formulas:
Gravitational Potential Energy
\(PE_{ gravity} = mgh\)
- where \(m\) is mass, \(g\) is gravity, \(h\) height of the object.
Spring Potential Energy
- also called Elastic potential energy.
- where \(k\) is the spring constant and \(x\) is the distance.
- This formula is known as Hooke's Law after Robert Hooke.
Non-conservative Energy
- A system that loses energy.
- Like when normal force loses energy when friction stops it.
Conservative Energy
- A system that doesn't lose energy.
- An example of this is a pendulum.
- because the kinetic energy and potential energy is just converting between each other.