Work & Power
The product of force and distance
What is Work?
A Machine
This is a device that changes a force
The number of times that the machine increases an input force
What is the mechanical advantage of a machine?
A rigid bar that is free to move around a fixed point
What is a lever?
The fixed point a lever rotates around
What is a fulcrum?
Motion
Work requires this
A unit of power, named after Scottish scientist James Watt
What is horsepower?
Actual mechanical advantage = output force divided by input force
What is the formula for actual mechanical advantage?
Ideal mechanical advantage = Input arm divided by the output arm
What is the formula for Ideal Mechanical Advantage?
A simple machine that consists of two disks or cylinders, each one with a different radius
What is a Wheel & Axle?
The rate of doing work
What is Power?
The work done by the input force acting through the input distance
What is work input?
The mechanical advantage in the absence of friction
What is the ideal mechanical advantage?
Lever, wheel & axle, inclined plane, wedge, screw & pulley
List the 6 types of simple machines
A slanted surface along which a force moves an object to a different elevation
What is an inclined plane?
This is the formula for work
Size of force
Direction of force
Distance over which a force acts
What 3 factors might a machine influence?
Ideal mechanical advantage = input distance divided by output distance
What is the formula for Ideal Mechanical Advantage?
First-Class Levers, Third-Class Levers
Which classes of levers can have a mechanical advantage less than 1?
A wheelbarrow
Give an example of a Second-Class Lever
no work is done
Complete this statement: If there is no movement...
Force exerted by a machine; the distance the output force is exerted through
What are output force/distance?
less than 100 percent
Complete this statement: Because there is always some friction, the efficiency of any machine is always...
A thin wedge
Which wedge - a thin or a thick - has a greater ideal mechanical advantage?
The closer together the threads are, the greater the IMA
How does the distance between threads on a screw impact its Ideal Mechanical Advantage?