• Force
  • Effects of Force

Force

Force is a pull, push or lift.
It is measured in Newtons (N)
A moving object is said to be in motion while an object at rest is said to be stationary.
Force is measured by the use of a spring balance.

Examples of Force

• Force of gravity (weight)
• Frictional force
• Magnetic force
• Inertial force

Effects of Force

• Makes an object to start moving
• Stops a moving object
• Change direction of a moving object
• Speeds up a moving object
• Change the shape of an object.

• Friction.
  • Advantages of Friction.
  • Disadvantages of Friction.
  • Ways of Reducing Friction
  • Ways of Increasing Friction.
• Levers
  • First Class Lever
  • Second Class Lever
  • Third Class Lever.

Friction.

This is a type of force that occurs between two objects that are in contact.

Advantages of Friction.

• It helps in walking.
• Makes it possible to produce fire using a match stick.
• Helps in writing in both boards and books.
• Helps in rubbing or erasing.
• Helps in braking of vehicles and bicycles.

Disadvantages of Friction.

• Causes wearing out of objects eg bicycle tyres,soles, shirts etc
• It makes work difficult eg its difficult to pull or puss an object on a rough surface.
• Production of unwanted heat.

Ways of Reducing Friction.

1. Using rollers.
2. Smoothing/Polishing surfaces.
3. Using lubricants
4. Streamlining.

Ways of Increasing Friction.

1. Spreading of some course materials on the slippery grounds e.g murram.
2. Using tyres with treads
3. Replacing worn out parts of tools
4. Replacing of shoe soles.
5. Applying of glue on the surfaces.

Levers

These are simple machines that makes work easier.

They have Load, Effort and Fulcrum.

Load:- This is the work to be done
Effort:- This is the part which is held in the tool.
Fulcrum:- This is the turning point of the tool or of the tool and the part which is held.

First Class Lever

Here the fulcrum is in between the load and the effort as in.

• Crowbar
• Claw hammer.
• A pair of scissor
• Pliers etc

Second Class Lever

Here the load is in betwee the fulcrum and effort

• Wheelbarrow
• Door hing
• Lid opener
• Bottle opener etc

Third Class Lever.

Here the effort is in between the load and the fulcrum

• Spade
• Spoon
• Fishing line etc

• Inclined planes.
• Single fixed pulley.

Inclined Planes.

These are tools that make work easier by increasing the effort distance.

Examples of inclined planes.

• Screw
• Screw driver.
• A road winding up a hill.
• Ladder.
• Staircase, escalators, ramps.
• Wedge

Single Fixed Pulley.

These are simple tools that make work easier by changing the direction of the force.
They are used to lift or raise load on higher surfaces.

A rope or string is put along the groove. The groove prevents the rope from slipping off.

Properties of a single fixed pulley.

• Makes work easier by changing the direction of the force.
• The effort distance and the load distance are equal.
• The effort force and load force move in opposite direction.
• The effort force and load force are equal

Uses of pulleys

1. Hoisting the flag.
2. To load or offload cargo at the ports.
3. Used in cranes