On a daily basis, we walk, we run, we play, we sit or stand. In all of these activities, we are changing the state of motion. We are bringing some object to rest or bringing it in motion. What is this called? What’re we actually doing? We’re actually applying ‘Force’ while bringing the object to rest or in motion. But what is a force? What are the effects of force? Let us scroll down and find out.
What is Force?
A ‘Force’ is a vector quantity that can be described as a push or pull on an object resulting from the object’s interaction with another object. Whenever there is an interaction between two objects, the objects experience an equal and opposing force on each other. In other words both the objects ‘exert force’ on each other. Force only exists as a result of an interaction. If there is no interaction, the objects no longer experience the force. Force is measured in units called Newtons (N), named after the famous scientist Sir Issac Newton.
Check out our detailed article on Force here.
Interactive Nature of Force
For force to exist, there must be an interaction between at least two objects. This interaction between the objects may or may not be physical. Pulling a rope or hitting a ball with a bat come physical interaction whereas forces like the magnetic force, electrostatic force, etc come under non-physical force.
Learn about different types of Forces here.
A force has both magnitude and direction. The magnitude of the force expresses the strength of a force. To completely determine a force both direction and magnitude must be specified; since the direction or magnitude of the applied force changes its effects.
Addition and Subtraction of Forces
‘Net Force’ is the total force exerted.
Therefore in the given diagram,
For the block A, the net force acting is
And, for the block B, the net force acting is . The two forces are subtracted since the forces are applied in opposite directions.
Effects of Force
A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate. When there’s the interaction between two objects they exert a force on each other, these exerted forces are equal in size but opposite in direction. When an object has several forces acting on it, the effects of force is same as one force acting on the object in a certain direction and this overall force is called the ‘resultant force’. The resultant force is essential to change the velocity of an object.
- If the resultant force is zero the forces on the object are balanced.
- If the resultant force acting on the object is ‘zero’ then: the object will remain stationary. In such a case the object will move at a steady speed in a straight line.
- If the resultant force acting on the object isn’t zero then: the object will either accelerate or decelerate.
Solved Example For You
Q. When a football is kicked, its shape changes for a fraction of a second. This is because:
a. force changes the shape of an object
b. force does not change the shape of an object
c. momentum changes the shape of an object
d. motion changes the shape of an object
Sol: a. force changes the shape of an object
Force changes the shape of an object. When a football is kicked, a contact force is applied and thus its shape changes.