Force, Motion, and Work The amount of work done on an object depends on the direction of the force and the object’s motion.

Amount of Work The amount of work done on an object can be determined by multiplying force times distance. When April lifts a trumpet or a tuba up the stairs, she does work.

Work and Power Power equals the amount of work done on an object in a unit of time. How much time would it take April to move her boxes upstairs if she runs?

Complete the table by calculating the power of the tow truck in each case.

Using Machines Using a ramp makes it easier for April to move the speaker onto the stage. What is April's output distance and force?

How would you complete the equations? Be sure to describe each quantity as large or small.

Mechanical Advantage The ratio of output force to input force is the mechanical advantage of a machine. Drums are tuned by tightening and loosening bolts. Drum keys make the bolts easier to turn. What is the key’s output force?

The graph shows input and output force data for three different ramps.

Inclined Plane An inclined plane allows input force to be exerted over a longer distance.

Wedge Instead of moving an object along an inclined plane, when a wedge is used the inclined plane itself moves.

Screw The threads of a screw act like an inclined plane to increase the distance over which input force is exerted.

Levers A seesaw is a type of lever in which the fulcrum is located halfway between the input and output forces. What is the name of a machine that matches each diagram?

Mechanical Advantage This graph represents the type of lever that is a hockey stick, with a shoulder as the fulcrum. What is the mechanical advantage of the hockey stick that is gripped at point D and hits the puck at point A? If it hits the puck at point B?

Three Classes of Levers The three classes of levers differ in the positions of the fulcrum, input force, and output force.

Levers in the Body Levers can be found throughout your body. In the last two panels of the diagram, where would the output force be? What is the class of lever for each part of the body?

Simple Machines in Sailboats You can find many simple machines on a sailboat. Where are the pulleys on the diagrams?

Types of Pulleys Pulley systems are classified by the number and position of the wheels they contain.

Wheel and Axle A simple machine made of two connected objects that rotate about a common axis is called a wheel and axle.

Piano movers use compound machines to get their job done. Calculate the mechanical advantage (MA) of each simple machine in the compound machine. What is the overall mechanical advantage?