Definitions
The ability to do work is called _______.
Energy
What is the equation for finding force?
F = m x a
Force = mass times acceleration
Batteries and lightning bolts are both examples of which of the 7 forms of energy we read about?
Electrical energy
As a diver dives into the water, what force is doing work on him?
Gravity
A transfer of energy that causes an object to move is called ________.
Work
What is the equation for potential energy?
PE = m x g x h
Potential energy equals mass times gravity times height.
The total mechanical energy of an object is the sum of its ___________ and ___________ energy.
In order for work to occur, what 2 things must be true?
1) A force must cause an object to move
2) The object must move in the direction the force is applied.
Energy that is stored as a result of position or shape is called _______ ____.
Potential energy
What is the equation for calculating the amount of work done?
W = F x d
Work equals force times distance
Which form of energy causes objects to change their states of matter when energy is added to or removed from atoms?
Thermal energy
This type of simple machine consists of an incline plane wrapped around a cone or a cylinder.
Screw
The process of changing energy from one form to another is called _______ __________.
Energy conversion
Find the amount of kinetic energy a 500kg car has traveling at a speed of 10 m/s.
KE = 1/2 x m x v2
KE = 0.5 x 500 x (10)2
KE = 250 x 100
KE = 25,000 Joules
Which type of energy is a form of energy that is reflected or emitted from objects and travels through space in the form of waves? (Examples include microwaves, UV rays, x-rays, gamma radiation)
Electromagnetic energy
This type of machine is made of a bar that rotates around a fixed point called a fulcrum. (Examples: A wheel barrow or a broom)
Lever
The number of times that a machine increases (or magnifies) input force is called the ___________ ___________ of the machine. This value describes how much easier a machine makes the work.
Mechanical advantage
How much power is exerted by a man that does 20 J of work in 4 seconds? Remember to label your answer in watts.
What does the Law of Conservation of Energy state?
Energy cannot be created nor destroyed; it can only be converted from one form to another or transferred between objects.
Machines change a force in 3 ways to make work easier. List 2 of the 3.
1) change the size of the force
2) change the direction of the force
3) change the distance over which the force is applied