LESSON – TYPES OF FORCE
- Meaning of Frictional Force
- Effects of Frictional Force
- Advantages and Disadvantages of Friction
- Ways of Preventing Friction
In the school and at home, we see many moving things.
We move about on our legs, vehicles move on roads, trains on the rails, aeroplane fly in the sky and ships sail on the seas.
Movement occurs when a force is applied on a thing or object.
That is, force causes things to move.
It can also prevent things from moving.
MEANING OF FORCE
A force is the power that makes an object to move by pushing or pull.
It opposed movement of an object or caused an object to move.
For example, car acceleration and break are good examples of push and pull forces.
TYPES/EXAMPLES/EVIDENCE OF FORCE
There are many types of forces, but only five are discussed below:
1. Muscular Force
2. Gravitational Force
3. Magnetic Force
4. Electrical Force
5. Frictional Force
1. MUSCULAR FORCE
Muscular force is the force applied to an object using the parts of body such as arms and legs.
For example – weight lifting (hands) and riding a bicycle (legs).
2. GRAVITATIONAL FORCE
Gravitational force is force that pulls an object down to earth.
3. MAGNETIC FORCE
Magnetic force is the force that attracts all magnetic materials to itself or push them further away from itself.
It is also pull or push force.
4. ELECTRICAL FORCE
Electrical force is the force that produces electric current.
5. FRICTIONAL FORCE
Frictional force is the force that opposed or slow movement.
6. BALANCE AND IMBALANCE FORCE
Balance force is the force that keep an object to rest while imbalance force is the force that makes an object to move from one place to another.
7. CONTACT AND NON CONTACT FORCE
Contact force is the force that is applied directly to an object while non contact force is the force that attracts objects from a distance.
EFFECTS OF FORCE
A force acting on an object may cause the object:
1. to change shape and size.
2. to start moving.
3. to stop moving.
4. to rotate.
5. to accelerate or decelerate.
INTRODUCTION OF FRICTIONAL FORCE
To stop a moving object, a force must act in the opposite direction to the direction of motion.
For instance, if you push your book across your desk, the book will move. The force of the push moves the book.
As the book slides across the desk, it slows down and stops moving.
The force that opposes the motion of an object is called friction.
MEANING OF FRICTIONAL FORCE
Friction is the force that opposes the motion of an object.
Friction can slow down or stops any moving objects.
Friction plays a vital role in our daily life.
Without friction we are handicap.
EFFECTS OF FRICTIONAL FORCE
The effects of the frictional force on objects are as follows:
1. It opposes the motion of all objects.
2. It slow down any moving objects.
3. It counteracts the acceleration of an object.
4. It prevents surfaces from sliding against each other.
5. It causes objects to accelerate.
ADVANTAGES OF FRICTIONAL FORCE
The advantages of friction are as follows:
1. It prevents slipping while walking.
2. It stops cars from moving.
3. We cannot fix nail in the wood or wall if there is no friction.
It is friction which holds the nail.
4. A horse cannot pull a cart unless friction furnishes him a secure Foothold.
DISADVANTAGES OF FRICTION
Despite the fact that the friction is very important in our daily life, it also has some disadvantages such as,
1. The main disadvantage of friction is that it produces heat in various parts of machines.
In this way some useful energy is wasted as heat energy.
2. Due to Friction, we have to exert more power in machines.
3. It opposes the motion.
4. Due to friction, noise is also produced in machines.
5. Due to friction, engines of automobiles consume more fuel which is a money loss.
METHODS OF REDUCING FRICTION
There are a number of methods to reduce Friction,
1. The use of lubricants
2. The use of grease
3. The use of ball
4. The design modification
1. THE USE OF LUBRICANTS
The parts of machines which are moving over one another must be properly lubricated by using oils and lubricants of suitable viscosity.
2. THE USE OF GREASE
Proper greasing between the sliding parts of machine reduces the friction.
3. THE USE OF BALL
Bearing In machines where possible, sliding friction can be replaced by rolling friction by using ball bearings.
4. THE DESIGN MODIFICATION
Friction can be reduced by changing the design of fast moving objects. The front of vehicles and airplanes made oblong to minimize friction.
Answer all the questions.
1. explain the meaning of force with appropriate illustrations.
2. state 5 types of force.
3. mention 5 effects of force on objects.
4. demonstrate the effects of force on materials.
5. explain the meaning of frictional force.
6. state 5 effects of friction.
7. mention 5 instance where friction is applicable in our daily activities;
8. list 4 advantages of friction.
9. state 4 disadvantages of friction.
10. mention 5 ways to reduce or prevent friction.