Levers and Linkages

What is a lever?

A lever is a simple machine that consists of a rigid bar that pivots around a fixed point called the fulcrum.

Why are levers used?

To lift or move loads with less effort by applying a force at one end

What are the three components of a lever?

Describe each component.

Give another term for each component

Fulcrum (Pivot)-The fixed point which the lever rotates

Effort (Input Force)-The force applied to the lever to move the load

Load (Output Force)-The weight/Resistance that is being moved

What is Mechanical Advantage

Refers to the ability on how machines are able to multiply the input force to accomplish work.

Give The Formula for Calculating the mechanical advantage for levers

Length of effort Arm/Length of Load arm

Give the three types of mechanical advantage a lever may produce and explain them

1. MA>1: The lever reduces the effort needed to move the load

2. MA=1: The lever changes the direction of the force but doesn’t reduce the effort

3. MA<1: The lever increases the speed or distance of movement but requires more effort

What is the structure of a first-class lever?

Effort—Fulcrum—Load

Give 3 advantages about a first-class lever

1. You can change the direction of the force.

2. It can give you a mechanical advantage, meaning less effort is needed to lift a heavy load, depending on the position of the fulcrum.​

3. It can multiply force.

Give 3 examples of a first-class lever

Seesaw

Crowbar

Pliers

What is the structure of a Second-Class Lever

Fulcrum—Load—Effort

Give 3 advantages of a second-class lever

• Gives a mechanical advantage—meaning you can move heavy loads with less effort.​

• The effort arm is always longer than the load arm.​

• Always multiples a force

Give 3 examples of a second-class lever

Wheelbarrow, Nutcracker, Bottle opener

What is the structure of a third-class lever

Fulcrum—Effort—Load

Give examples of a Third Class Lever

Broom

Fishing Rod

Tongs

List the two purposes of a third-class lever.

Increases the speed or distance of movement; requires more effort

Mechanism

Moving parts in a machine that work together

Input

Energy or movement inserted into a machine

Pivot

Fixed or movable connection in a lever or linkage that allows force or motion to be directed where it is needed

Output

energy or movement that is the result of the machine doing work

Linkage

A mechanism connecting many levers together

What are linkages used for

To reach over a distance or change the direction of movement, or to increase the degree of movement or change the distance of movement

Give a reason why the direction of a force in a first-class lever can be changed

The pivot forces the input and the output to move in different directions since it is placed between them.

At which point are two first-class levers linked?

The Fulcrum

What can the fulcrum of a linked first-class lever create, and what can the creation be used for?

Mechanical Advantage

Cutting

Gripping

Clamping objects

Linked first-class lever

Two paired structures used to move an object.

Identified by the effort and load being applied at both ends while two structures turn about a fulcrum in the centre.

What does the effort in a second-class lever force?

It forces the input and output to move in the same direction

Single first-class lever

A single rigid structure used to move an object.

It is identified by the load and effort being applied at both ends while the structure turns about a fulcrum in the center.

Single second-class lever

A single rigid structure used to move an object.

It is identified by the effort being applied at one end. The fulcrum is in the opposite end and the load is in the center

Linked Second-Class Lever

Two paired structures used to move an object.

It is identified by the effort being applied at one end.

The fulcrum is on the opposite end.

The load is in the center.

What can the mechanical advantage for a linked second-class lever do? And why?

Lift, Crush, and Squeeze Objects. Because it is strong.

How is the mechanical advantage of a second-class lever determined

On how close the load is to the fulcrum.

Single-Third Class Lever

A single rigid structure used to move an object. It is identified by the effort being applied in the center. The fulcrum is at one end and the load is at the other end

Linked third-class lever

Two paired structures used to move an object. It is identified by the effort being applied in the center , the fulcrum is at one end and the load is at the other