ch 12-13 Flashcards
(47 cards)
work
when you exert a force on an object that causes the object to move some distance
how do you know if work is being done on an object
if an object moves in the same direction in which the force is exerted
joule
measurement for work, 1 joule is to move an object a distance of one meter
power
the rate at which work is done
a machine makes work easier by changing at least one of three factors, what are the three factors
a machine may change the amount of force you exert, the distance over which you exert your force, or in the direction in which you exert your force
machine
a device that allows you to do work in a way that is easier
input force
the force you exert on the machine
input distance
the distance the input force moves the machine
output force
the force the machine exerts on an object
output distance
the work the machine dose over another distance
input work
the input force times the input distance
output work
the output force times output distance
mechanical advantage
the number of times a machine increases a force exerted on it
efficiency
compares the output work to the input work of machine
what are the six basic types of simple machines
incline plane, wedge, screw, lever, wheel and axle, and pulley
most of the machines in your body are what?
levers that consist of bone and muscles
what is the ideal mechanical advantage of a compound machine
it is the product of the individual ideal mechanical advantages that make it up
incline plane
a flat, slope
wedge
a device that is thick at one end and tapers to a thin edge at the other end
screw
can be thought of as an incline plane wrapped around a cylinder
lever
is a ridged bar that is free to pivot or rotate on a fixed point
fulcrum
the fixed point that a lever pivots around
wheel and axle
a simple machine made out of two circular or cylindrical objects fasted together that rotate about a common axis
pulley
a simple machine made of a grooved wheel with a rope or cable rapped around it
