Work and Machines Review
Unit used to measure work Joules
The rate at which work is done Power
Unit of power Watt
Three ways a machine can make work easier Increase the distance Change the direction of the force Multiply the force
Device that does work with only one movement and changes the size or direction of the force Simple Machine
Two things that must happen for something to be considered work. The object must move The movement must be in the direction of the force.
What’s work? A scientist delivers a speech to an audience of his peers. A body builder lifts 350 pounds above his head. A mother carries her baby from room to room. A father pushes a baby in a carriage. A woman carries a 20 kg grocery bag to her car?
What’s work? A scientist delivers a speech to an audience of his peers. No A body builder lifts 350 pounds above his head. Yes A mother carries her baby from room to room. No A father pushes a baby in a carriage. Yes A woman carries a 20 km grocery bag to her car? No
Formulas
Work Force x Distance
Power Work Time
Write the handy dandy formula rearranging circles for work and power.
Name the Machine
ramp Inclined Plane
Bar that rotates around a fixed point Lever
Inclined plane with one or two sloping sides Wedge
A winding mountain road Inclined Plane
Two or more simple machines working together Compound Machine
Knife Wedge
Leaf rake Lever
Mechanical Advantage
The amount by which a machine multiplies the input force Mechanical Advantage
What would be the mechanical advantage of the following?
What would be the mechanical advantage of the following?
What would be the mechanical advantage of the following? How much would the weight feel like it weighed?
Which would have the most MA and Why? 1 3 2
If used as a lever, which would have the most MA and why?