Section A- Mechanical devices (3.1.5)

Pulling force exerted by each end of an object such as a string or rope.

A twisting force

A pushing force/ being squashed

A bending force is applied at an angle causing a material to be in compression and tension at the same time.

A force across a material, eg scissors cut by applying a shear force.

Load ÷ effort

Fixed pulley

Block and tackle pulley

One direction

A back and forth movement.

swinging back and forth

Making something easier to move/ lift.

Have fulcrum between force and load e.g. Pliers

Have fulcrum one end, effort at the opposite end, load in the middle e.g. Wheelbarrow.

Fulcrum one end, load opposite, effort in the middle e.g. Tweezers

It maintains the direction of the input motion- meaning that the output motion goes in the same direction.

It changed the input motion by 90 degrees. Making vertical motion horizontal or horizontal vertical.

Steady rise and fall

Rapid rise and fall with long dwell

long dwell followed by steady rise and sudden drop can only turn in one direction

Slight rise and fall with no dwell period

The force that causes rotation

Mainly used to change rotary motion into reciprocating motion through use of a follower.

The thing moving up and down.

Used to rotate the shaft, which rotates the cam.

Toothed wheels that mesh to transfer motion from one part of a machine to another.

Transmit rotary motion and torque (causes rotation). Different sized gears increase/ decrease speed of rotation.

The driver gear (input) turns the driven gear (output). the gears turn in opposite direction.

Used to change direction of rotation so driver gear turns in the same direction as driver gear. Size does not affect speed.

Speed of driver gear / gear ratio

Large driver gear with small driven gear.

Number of teeth on driven gear/ number of teeth on driver gear e.g. 20: 40 = 1:2

A drive belt (loop of flexible rubber) connects two or more pulleys together and the belt transfers power from the pulley to receiving system.