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# physical science

### science notes

Question | Answer |
---|---|

what is the transfer of energy to an object by the application of a force that causes the object to move in the direction of the force? | work |

how is work calculated? | work is calculated by multiplying the force by the distance over which the force is applied |

How must the force used to calculate work be applied | the force used to calculate work must be applied in the direction of the object's motion |

what is the equation for work | work=force times distance or can be written as w=FD and rearranged it is distance=work divided by force or can be written as D=W/F |

what is work when an object is not moving or at rest? | when an object is at rest the work is zero |

if the object has not moved any distance at all and you are applying a great force is work being done? | it would not because the object is not moving so the work equals zero no matter how much force you apply |

how is work expressed? | Newtons times meters |

what is work measured in? | joules because when you combine newtons times meters you would get the term joules |

what is one joule equal to? | one joule is equal to one kilogram times meter squared per second squared |

example of that | 1Newton times meter= 1kilogram times meter squared/second squared |

what are all these units? | they are equivalent |

what do these equivalent units help you do? | the equivalent units often help you cancel out other units in a problem |

example of work? | the example would be when you lift up an apple |

what is the quantity that measures the rate at which work is done or energy is transformed? | power |

what is power? | power is the rate at which work is done, or how much work is done in a given amount of time |

what is the power equation? | power=work divided by time or can be written as p=w/t and can be rearranged as Work=Power times time or can be written as W=P*T and rearranged again for time is Time=Work divided by power or can be as T=W/P |

example of power? | running a given distance instead of walking |

what is the Si unit for power? | the Si unit for power is the watt(W) |

what is one watt equal to? | one watt is the amount of power needed to do one joule of work in one second |

example again? | the apple |

What do machines help you do? | Machines help do work by changing the size of an input force, the direction of the force, or both |

What do machines help you do continued on? | Machines help redistribute the work that we put into them and can change the direction of an input force and machines can also make the force greater by decreasing the distance over which the force is applied |

what is the force greater by decreasing the distance over which the force is applied called? | the process is called multiplying the force |

examples of machines and mechanical advantage? | using a jack instead of picking up a car with your hands |

what is mechanical advantage? | Mechanical advantage is an important ratio between the output force and the input force and is a number that describes how much the force or distance is multiplied by a machine |

what is the definition of mechanical advantage? | Mechanical advantage is a quantity that expresses how much a machine multiplies force or distance |

what is an example of mechanical advantage? | an example of mechanical advantage is a ramp which makes work easier by multiplying the force that is applied, |

what is mechanical advantage equal to? | mechanical advantage is equal to the ratio between the the input distance and the output distance if friction is ignored |

what is the equation for mechanical advantage? | Mechanical Advantage=output force divided by input force and can be arranged as output force=input force times mechanical advantage and can also be rearranged again to input force= Output force divided by mechanical advantage |

what happens when a machine has a mechanical advantage greater than one? | When a machine has a mechanical advantage greater than one it multiplies the input force this machine helps you life heavy objects |

what happens when a machine has a mechanical advantage less than one? | When a machine has a mechanical advantage less than one it does not multiply the force but increases the distance and speed |

Created by:
krauser