| Term | Definition |
|---|
| Work (word formula) | The force applied times the distance the object moves while the force is acting |
| Unit of measure for Force | Newtons |
| Unit of measure for Work | Joules |
| Unit of measure for Power | Watts |
| formula for work | W=F x d |
| formula for power | Power=work/time |
| What's the difference between a simple and complex machine? | A complex machine is made up of subsystems where simple machines are not. |
| What do machines do? | Machines reduce the force to do a constant amount of work. |
| What's a simple machine? | One of six elemntary devices that change the size or direction of a force. Simple machines can be combined to form complex machines |
| Why does work remain constant with a machine? | Because friction adds work. |
| Power | The rate at which work is done. |
| What is energy? | The capacity to do work |
| Why is it helpful to use a machine? | Because you apply less force to lift the same amount of weight. |
| Give 6 examples of a simple machine. | (Lever, Pulley, Wheel and axel, Wedge, Screw, and Inclined plane.) |
| What's a complex machine? | A complex machine is made up of one or more simple machines. |
| Give 3 examples of complex machines. | Bicycle, Car, Lawn mower. |
| What's a subsystem? | A system that's part of a larger system. |
| How are work and power different? | Work doesn't depend on time where power does. |
| Define work. | The result of using force to move an object over a distance. |
| Unit of measure for distance. | Meters. |
| 1 kg ( = N? ) | 10N (= kg? ) |
| 1 J ( = kj? ) | .001kj ( = J? ) |
| kilo ( = ? ) | 1000 ( = ? ) |
| Why is it helpful to use machines? | Because they reduce the amount of force needed to do a constant amount of work. |
| Why can't all P.E. be converted to K.E.? | Because some of the energy can be converted to heat, chemical, mechanical, or light energy and used in friction. |
| How can P.E. be given to an object? | By stretching, compressing, or raising the object. |
| How can K.E. be given to an object? | By releasing, pushing or moving the object. |
| What does a pendulum do work on? | It puts force, therefore work, on the air to push it out of the way. |
| Define chemical energy. | A form of P.E. that's stored in fuels, foods, and other chemicals and that's released by chemical reactions. |
| Define energy converter. | A physical system in which energy is changed from one form to another. |
| Define mechanical energy. | The kinetic energy of moving objects. |
| What do work and energy share? | They share the same unit of joules. This is required as each can produce the other. |
| The equation for P.E. | height x weight; N x m; joules |
| What's chemical energy used for? | Motion, but is also used to maintain body temperature in mammals and birds as well as powers lungs, hearts, and brains. |
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