Mechanical Advantage Basics

Mechanical Advantage Basics

I will be able to calculate the mechanical advantage of simple machines

Mechanical Advantage (MA)

• The ratio of the force that performs the useful work of a machine to the force that is applied to the machine.

• The MA is the number of times a machine multiplies your effort force.

• The greater the MA the less effort force is required for the machine.

Pulleys

• MA = the number of supporting ropes

• Ex: The MA of 1 fixed pulley is 1.

• Ex: The MA of 2 fixed pulleys and 2 moveable pulleys is 4.

Inclined Plane

• A flat surface set at an angle used to help raise or lower objects.

• MA = length of sloped surface divided by the height of the inclined plane. 

Multiple Choice

Which inclined plane has the greatest MA?

• Inclined plane with a length of 30 cm and a height of 14cm?

• Inclined plane with a length of 40 cm and a height of 14cm?

• Inclined plane with a length of 50 cm and a height of 14cm?

• Inclined plane with a length of 60 cm and a height of 14cm?

Screw

• A cylinder with a spiral ridge or thread running around the outside that can be turned to seal an opening, apply pressure, adjust position, etc.

• MA= circumference of where the effort is applied divided by the pitch.

Multiple Choice

The distance between the threads on a screw.

• pitch

• circumference

• threads per inch

• diameter

Calculate MA

• Calculate the MA of a screw with a circumference of 0.79 inches and a pitch of 1/8

• MA = 0.79 * 8

• MA = 6.3