How can you define physical force? On scientific grounds, force can be defined as the interaction between objects with mass which results in a pull or push. When force is applied to a stationary object, it results in motion. Secondly, when force is applied to a moving object, it results in velocity change (acceleration) or it counters the acceleration to cause a stop on the motion. Newton's second law brings forth a force formula; F= m*a, where "a" is acceleration, "m" is mass and "F" is the resulting force. The most famous universal accepted System Internationale (SI) unit of force is Newton (N). Other units of force used are kilogram-force (kilopond), dyne, pound-force or poundal.

Additionally, there are other force facts you should know. First, the force has magnitude and direction which makes force a vector. Force is also an equilibrium where the force acts on an object but does not cause that object to move.

6 Main Types of Physical Forces

The question of how to define physical force brings several characteristics, hence types of force. Below are types of force.

1. Normal force

When you place your laptop on a table, it experiences the pull of gravity. On the other hand, the normal force is also experienced which is the upward push exacted under the bottom of the laptop by a table. The normal force is the force that makes your computer rest on the table surface well regardless of its weight. When an object is placed on a surface but its weight or gravitational pull is greater than the normal force, that is the time you see surfaces collapsing or bending.

2. Gravity

Gravity is the pull on an object towards the center of the earth. All objects have a kind of force that draws (pulls) them towards the center of the earth. Gravitational force is always equal to the weight of an object.

3. Applied force

The applied force is the kind of force exerted on an object by another object or a person. For example, when a table, desk or chair is pushed, the applied force is thereby witnessed and used. Secondly, when you want to switch off the lights, you are compelled to use force (applied force) on the switch button.

4. Frictional force

When an object moved over another object, the frictional force is experienced. In your effort to answer how to define physical force, the force produced when an object gets rubbed against another object in the opposite direction is called friction force. There are two types of friction force: static and sliding force. The friction force helps all living creatures to walk without sliding.

5. Tension force

When a wire, rope, cable or a string get pulled from both ends, a force called tension force is transmitted through it. Tension force can also result after tying a rope from both ends on two posts. The kind of pull experienced from both ends and distributed through the wire is what is called tension force.

6. Spring force

The way springs work can help answer how to define physical force. When a spring is stretched or compressed, the force created in such a time is called spring force. For a spring that obeys Hooke's Law, the type of spring force built (its magnitude) is directly dependent and proportional to the level or amount of compression or stretch acting on that same spring.

Main Examples to Feel Different Forces

Force is a typical daily happening. Force is experienced when an external pull or push is exacted on an object. Below are daily happening or examples.

• A moving bike stops when brakes are applied

For a moving bike to stop, force must be used. When you hold a bicycle's brake, the brake wire transmits some energy (force) to the brake pads which exacts force on the wheel's rim to cause a friction force, hence stopping the bike.

• A bull is pulling the cart due with force

For a stationary cart to move, the applied force is used. When the bull starts to move, and a pulling force is applied to the cart, forward motion is created.

• A man pulls the door of the room

Whether a door is being shut or opened, force must be applied. The applied force is thus needed from a man to set it in motion whether to close or open.

• Gravitational force attracting the ball moving up

When a ball is kicked up in the air, force gets applied from a human hand or leg. After kicking, the ball is set in motion up in the air although at some point the momentum (motion) reduces due to gravitational pull. Thus, the ball cannot stay up there, the forces of the earth called gravitational force pulls the ball down towards the center of the earth.

Take Home Message

If you still wonder how to define physical force, it is a "must" to create a force in almost everything to bring about work. There would be no life without force. Force is everywhere and everything, from cooking, standing, walking, sitting, driving, writing and many more situations.