# Lesson Notes By Weeks and Term - Junior Secondary School 1

FORCES

SUBJECT:  BASIC SCIENCE

CLASS:  JSS1

DATE:

TERM: 3RD TERM

REFERENCE

• Precious seed BASIC SCIENCE FOR JUNIOR SECONDARY SCHOOLS BOOK 1

WEEK THREE

FORCES

A force can be defined as any action that makes or tries to move, stop or alter the speed of a body in a given direction.

TYPES OF FORCE

There are two types of force namely:

1. Contact force
2. Non-contact

CONTACT FORCE

These are  forces which sources are in contact with the body to which they are applied. The contact forces could be direct or indirect. Examples of contact forces are; Push, Pull ,Tension, Friction, Upthrust.

NON- CONTACT FORCES

These are forces which the sources do not require contact with the body they are applied. These forces act through a region in space called field. They are therefore also called FORCE FIELDS. Example include: Gravitational force, Electric force, Magnetic force

MAGNETIC AND GRAVITATIONAL FORCES

In a bar magnetic, there is North pole end south pole end, the like poles repel each other while unlike poles attract each other. Two magnets can attract each other when they were still some distance apart. Also magnet can attract iron fillings before the magnet came in contact with the iron fillings. These magnets came in contact with the iron fillings. This phenomenon shows that magnetic force act over an area around the magnet. Thus a magnetic force is called a field force which acts over an area.

GRAVITATIONAL FORCES

The force by which the earth attracts all objects to itself is called the force of gravity or gravitational force. This is the reason why objects above the earth fall down to the earth.

The light objects like feathers, children balloon which do not fall immediately to the earth are supported by air, but they eventually fall to the earth.

EVALUATION

1. Explain the magnetic force.
2. What do you understand by gravitational force ?

• Precious seed BASIC SCIENCE FOR JUNIOR SECONDARY SCHOOLS BOOK 1 page 152-161
• Nigerian Basic Science Project pg 120-125.

GENERAL EVALUATION

1. Explain the magnetic force.
2. What do you understand by gravitational force?
3. Distinguish between contact force and force of gravity
4. How would you demonstrate a magnetic force?
5. Name two contact and two non-contact forces.

WEEKEND ASSIGNMENT

1. Which of the following statement is false A. a force changes the shape of a body
2. forces may be balanced or unbalanced  C.  a force cannot change the direction of a moving body   D.  a force changes the speed of object
3. Which of the following is not a type of force? A. electrical B. contact C. magnetic    D.  reversible
4. When a canoe – man paddles backwards in the water, the canoe moves forward this shows that A.  forces occur in pair B. contact force is acting C. a force is not involved D. water is pushing the canoe.
5. The gravitational force can be found A. on the earth B. in the moon C. around the planets D. in the galaxy
6. The magnetic force is also known as ___ A. pulse B. electrical C. field force
7. gravitational force

THEORY

1. Distinguish between contact force and force of gravity.
2. How would you demonstrate a magnetic force?
3. Name two contact and two non-contact forces.