Machines

machine

device that changes a force

1. size of the force
2. direction of the force
3. distance of which the force acts

3 things a machine can change

friction; less

due to _ _ _ the work done by the machine is always _ _ _ than the work being done on the machine

input force

the force you exert on a machine

input distance

the distance the input force acts through

input work

work done by input force and input distance

output force

force exerted by a machine

mechanical advantage

the number of times that a machine increases an input force

actual mechanical advantage

MA of a machine determined by measuring the actual forces acting on it

output force/input force

formula for actual mechanical advantage

1. lever
2. wheel and axle
3. inclined plane
4. wedge
5. screw
6. pulley

what are the 6 kinds of simple machines?

lever

rigid bar that is free to move around a fixed point

fulcrum

fixed point that the bar rotates around

input arm

distance from input force to fulcrum

output arm

distance between output force and fulcrum

input arm/output arm

formula for ideal mechanical advantage

fulcrum

where the _ _ _ is determines the type of lever

1st class lever

fulcrum is between the input force and output force

seesaw, scissors

example of 1st class lever

2nd class lever

output force is between fulcrum and input force

wheelbarrow

example of 2nd class lever

3rd class lever

when the input force is between the fulcrum and the output force

wheel and axle

simple machine made of two circular objects each with a different radius that rotate on a common axle

steering-wheel, screwdriver

example of wheel and axle

inclined plane

slanted surface along which a force moves an object to a different elevation

ramp

example of inclined plane

wedge

a device that is thick at one end and tapers to a thin edge at the other end

axe, doorstop

example of wedge

greater

the longer and thinner the wedge, the _ _ _ the mechanical advantage

screw

inclined plane wrapped around a cylinder

bottle-cap, jar, screw

example of screw

pulley

simple machine that consists of a rope wrapped around a groove in a wheel

fixed pulley

a wheel attached to a fixed location

flagpole, blinds

example of fixed pulley

input

fixed pulley only changes in the direction of the _ _ _ force

moveable pulley

attached to the object being moved; not a fixed location

sailboat, window washing device

example of moveable pulley

direction; size

moveable pulley changes _ _ _ and _ _ _ of input force

pulley system

combining fixed and moveable pulleys

compound machine

combination of two or more simple machines working together

crane

example of compound machine