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Describe the types of force

      

Describe the types of force

  

Answers

Moraa
1.Gravitational force
It is the force that attracts all objects towards the centre of the earth. It is unique in every planet. The earth’s
gravitational force is that force of attraction between the earth and the body. The pull of gravity on a body
towards the centre of the earth is called its weight. Weight varies from place to place although its mass remains
constant.
The weight of a body is the product of its mass and the gravitational force acting on the body
i.e. weight =mass *gravitational force.
2: Tension
When a string is stretched or compressed at both of its ends, it experiences a force called tension. A stretched or
compressed material will tend to regain its original shape when the stretching or compressing force is
withdrawn. Materials that do not break after stretching or compression is said to be elastic.
Upthrust
When an object is immersed in a fluid (liquid/gas), there is always an opposite upward force acting on it. This is
called upthrust force.
NB. There is no upthrust force in a vacuum.
Upthrust force = Weight of object when in air -- Weight of the object when immersed in fluid (Apparent weight of the object)
3: Friction force
This is the force that tends to oppose the motion of one object over another when they are in contact. Friction
force is useful in many ways for instance during walking, writing, applying brakes, lighting a match stick, etc.
Friction in fluids is called viscous drag or simply viscosity.
5: Magnetic force
A magnet can either attract or repel a magnetic material. This force of attraction or repulsion is called magnetic
force. Materials that are not affected by a magnet are said to be non-magnetic materials.
6: Electrostatic force
This is the force of attraction or repulsion between static charges. Like charges repel while unlike charges attract.
Electrostatic force is evident in the following cases:
A plastic pen or ruler rubbed on dry air picks up small pieces of paper placed on a table.
Such a pen can attract a stream of water from a water tap.
A glass window wiped using a dry piece of cloth on a dry day immediately attracts dust particles.
Brushed shoes attract dust particles.
When combing a dry hair, a cracking sound is produced.
All these are as a result of attraction between the formed charges and the opposite charges.
7: Centripetal force
This is the force that constraints a body to maintain a circular path as it move. It is usually directed towards the
centre of the circle.
8: Action and reaction
Action and reaction are equal and opposite forces. When a block of wood rests on a table its weight is exerted on
the table. This is action force. The table on the other hand exerts an equal upward force on the block of wood.
This is reaction force and it prevents the block from sinking down below the table.
9: Cohesive and adhesive force
Cohesive force is the force of attraction between molecules of the same kind e.g. force between water molecules.
Adhesive force is the force of attraction between molecules of different kinds e.g. force between water molecule
and the surface of glass.
10: Surface tension
The cohesive force between the molecules of a liquid gives it some strength. The surface can thus resist
stretching. Surface tension is the force that makes the surface of the liquid to behave like a fully stretched elastic
skin.
Surface tension allows light insects to rest over water without sinking. a steel razor blade or needle floats on
water if placed carefully but sinks when soap solution or kerosene is placed around it. Also if one end of the
needle is pressed into the water, it breaks the surface tension and the needle sinks.
Molecular explanation of surface tension
Moraa orina answered the question on April 6, 2018 at 14:53

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