Energy, Work & Power Flashcards
Energy is measured in…
Joules (J)
Can energy be created or destroyed?
Neither
The formula for kinetic energy is…
Ek = 1/2mv^2
The formula for work is…
W = Fd
W = Fd is the formula for…
Work
What is Chemical Potential Energy?
Energy that is stored in the bonds between atoms. Found is substances such as petrol and food.
What is Electrical Energy?
The movement of electrically charged particles. Found in wires, generators and lightning.
What is Gravitational Potential Energy?
Energy stored in objects due to their height above the ground.
What is Heat Energy?
Caused by the movement of particles. Found inside all heated/hot objects.
What is Light Energy?
The energy of electromagnetic waves. Found in microwaves, X-rays and visible light.
What is Sound Energy?
Energy produced by vibrating objects. Examples include speech, ultrasound and music.
What is Kinetic Energy?
Energy of an object due to its motion. Examples include moving cars, running and swimming.
What is Elastic Potential Energy?
Energy stored in stretched or squashed objects. Examples include springs and rubber bands.
What is the formula for Gravitational Potential Energy?
Change in Gravitational Potential Energy (Ep) = mass (m) x gravity (g) x change in height (h) or Ep=mgh
What is power?
The rate at which work is done.
What is the formula for Power?
Power (p) = Work (W) divided by Time (t) or P=W/t
An object has more kinetic energy if…
its mass or speed is greater
When is work done on an object?
Work is done on an object when a force causes the object to move in the direction of the force. The amount of work done on an object depends on the force applied to that object and the distance the object travels.
A book that weighs 4N and is lifted onto a shelf 3m higher than its original position, calculate the work done
w= F x d
= 4N x 3m
=12 j
What does the law of conservation of energy state?
Energy can’t be created or destroyed, it can only be transformed or transferred from one form to another
Why will a ball never rebound to the same height it was dropped from?
The rebound energy is smaller than the the initial energy because not all of the kinetic energy is conserved, it is transferred into other types of energy such as heat and sound.
