# data[].attributes.body
Green: chapter 7, blue: chapter 8, pink: chapter 9

# data[].attributes.body
The human body is complex machine that includes a number of simple machines—levers. Levers provide the body with the ability to accomplish tasks. A classic example of a third class lever is your forearm.

# data[].attributes.body
The fulcrum is at the top of the neck. The muscles in the neck provide an input force that allows you to raise your head.

# data[].attributes.body
The mechanical advantage of a ramp is the ramp length divided by the height of the ramp. A ramp is a simple machine that allows you to raise a heavy object , such as a wheeled cart, with less force than you would need to lift it straight up. A wedge is like a ramp that can work while in motion (a ramp is always stationary.) A wheel rotates around a rod called an axle. The wheel and axle move together to move or lift loads.

# data[].attributes.body
Gears can transfer motion and force when the teeth of one gear press on the teeth of another gear as each gear rotates around a shaft. A gear ratio is the ratio his output turns to input tubes for a pair of gears.

# data[].attributes.body
All levers include a stiff structure that rotates around a fulcrum. Levers are useful because you can arrange the fulcrum and input and output arms to adjust the mechanical advantage of the lever. Using the length of the lever arms , mechanical advantage can also be calculated by dividing the length of the input arm by the length of the output arm.

# data[].attributes.body
Mechanical advantage is the ratio of output force divided by input force.

# data[].attributes.body
A simple machine is an unpowered mechanical device that accomplishes a task with only one movement. Lever is a stiff structure that rotated around a fixed point called a fulcrum. Gear is a rotating wheel with teeth that transfers motion and forces to other gears or objects

# data[].attributes.body
A machine is a device with moving parts that work together accomplish a task. Input in machines is forces , energy , or power supplied to make a machine accomplish a task. The output is what the machine does for you , like going fast or climbing a steep hill.

# data[].attributes.body
Power is the rate of doing work or moving energy. Power is equal to energy (or work) divided by time. Watt (W) is a unit of power equal to 1 joule per second. A horsepower (hp) is a unit of power equal to 746 watts.

# data[].attributes.body
Energy drives all the process in nature , from winds in the atmosphere to nuclear reactions occurring in the cores of starts. In the environment , efficiency is interpreted as the fraction of incoming energy that goes into a process.

# data[].attributes.body
Efficiency is the ratio of usable output work divide by total input work. Efficiency is often expressed a percent , with a perfect machine having 100 percent efficiency. A perfect car would have an efficiency of 100 percent.

# data[].attributes.body
Work input is the work that is done on an object . Work output is the work that an object does as a result of work input. The total energy of work output can never be greater than the total energy of work input.

# data[].attributes.body
Work is only done by the part of a force that acts in the same direction as the resulting motion. Work some against gravity is equal to weight.

# data[].attributes.body
Energy is always required to do work. Doing work always means transferring energy. The energy might  be transferred to the object to which the force is applied to, or it may go somewhere else.

# data[].attributes.body
Work is  a form of energy that comes from force applied over distance. A force of 1 newton does 1 joule of work when the force causes 1 meter of motion in the direction of the force.

# data[].attributes.body
Energy can never be created or destroyed , energy could just be transformed from one form to another. The total amount of energy in the universe is constant.

# data[].attributes.body
Systems change energy flows and changes from one part of the system to another. Parts of the system may speed up or slow down, get warmer or colder, or change in other measurable ways.

# data[].attributes.body
Kinetic & potential energy video

# data[].attributes.body
In physics the word work has a very specific meaning. Work is the transfer of energy that results from applying a force over a distance . Work is the force applied times the distance.

# data[].attributes.body
Energy describes the abillity of things to change themselves or to cause change in other things. Some examples of this changes are temperature, speed, position, or pressure or any other physical variable. A joule (J) is the unit of measurement of energy.

# data[].attributes.attachment_link.title
Renewable Energy Explained in 2 1/2 Minutes

# data[].attributes.body
Radiant energy is the energy of electromagnetic and gravitional radiation.

# data[].attributes.body
Chemical energy is the form of energy stored in the nuclei of atoms (paricles of matter.) Some examples of chemical energy are food, gasoline, and batteries.

# data[].attributes.body
Kinetic energy is the energy of motion. Kinetic energy can be easily converted into potential energy.

# data[].attributes.body
In physics , potential energy possessed by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors.

# data[].attributes.body
In physical science, mechanical energy is the sum of potential and kinetic energy. Mechanical energy that is related to motion or position.

# data[].attributes.body
Nuclear energy is a form of energy stored in the nuclei of atoms (particles of matter.) Nuclear energy is transformed to heat that eventually escapes the Sun as radiant energy.