3.2 Understand machines
▪expressed as a percentage compares output work to input work of a machine
What is effeciency?
▪the SI unit of work is the
What is the newton/meter (n*m) or joule?
The most basic device for making work easier
What is a simple machine?
A simple machine made of two connected objects that rotate about a common axis
Whsat is a wheel and axle?
▪two simple machines that take advantage of turning:
What is the pulley and the wheel and axle?
▪the number of times a machine increases the force exerted on it.
What is Mechanical advantage?
work is done on an object when
What is the object moves in the same direction in which the force is exerted?
an inclined plane allows you to
what is exert your input force over a longer distance?
radius of wheel / radius of axle(IMA=Rw/Ra)
What is the Ideal Mechanical advantage of a wheel and axle?
This simple machine decreases the amount of input force needed but does not change the direction of the force and has a mechanical advantage of two
What is a Movable Pulley
Since machines do not reduce the work you do your output work can
WHat is never be greater than your input work?
to do work on an object, the object must move some distance as a result of your force, if the object does not move,___________________ , no matter how much force is exerted
What is no work is done?
▪Three simple machines that are closely related. These form the inclined plane family
What is the inclined plane, the wedge, and the screw?
machine that combines two or more simple machines
What is a Compound machine?
a device that is thick at one end and tapers to a thin edge at the other end
What is a wedge?
▪Because of _________, actual mechanical advantage is always less than ideal mechanical advantage.
What is friction?
the amount of work done on an object in a unit of time is called
What is power?
the threads of a screw act like an incline plane to increase the distance over which you
What is exert the input force?
a simple machine made of a grooved wheel with a rope or cable wrapped around it.
What is a pulley?
An inclined plane wrapped around a cylinder
What is a screw?
▪machine makes work easier by changing at least one of three factors:
What is the amount of force you exert, the distance over which you exert your force, or the direction in which you exert your force?
The amount of work you do when you exert a force of 1 N to move in object a distance of 1 m.
What is a Joule?
when you use a wedge, instead of moving in object along the incline plane, you
What is move the inclined plane itself?
within a compound machine, the output force of one simple machine becomes
What is the input force of another simple machine?
▪the fixed point The lever pivots around
What is a fulcrum