Question

what is contact force
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Answer 1

To understand what are contact forces, let us study the following cases .

1. When you pull a coiled spring (whose one end is fixed to a wall), you apply an effort on the spring. The spring gets stretched. This is an example of contact force as you are in contact with the spring.
2. When you kick a football or pull a cart, contact force is applied.

Contact forces are forces which act only when objects are in physical contact with each other and bring about changes.

Some important contact forces are :

• Muscular force
• Mechanical force
• Frictional force

Muscular force :

You can lift a bucket with your hands, kick the football and pedal the bicycle with your legs. In all the above examples, to apply a force on an object, your body (hands or legs in these examples) comes in contact with the object.

Where does this force come from ?

This force is caused by the action of muscles in our body. The force resulting due to the action of muscles is known as Muscular force. Since, our body is in contact with the object, muscular force is a contact force. We use muscular force during walking, running, pushing, pulling and lifting certain objects. Animals like elephants and bullocks perform various tasks such as carrying heavy loads, ploughing fields, pulling carts, etc., with the Muscular force

Mechanical force :

The force exerted by a machine to do some work is called mechanical force. No machine can produce force on its own, it needs some kind of energy.

For example :

1. A car moves only when its wheels move, the force exerted by the car engine to move the wheels of the car is the mechanical force. A car engine burns fuel (e.g., petrol) to generate mechanical force.
2. Sail boats use the energy of wind to produce mechanical force which propels the boats.
3. Windmill also uses the energy of wind to produce mechanical force, which rotates the blades of the windmill that runs the electric generators to produce electricity.

Frictional force (or force of friction) :

A ball rolling along the ground gradually slows.down and finally comes to rest. You find no visible force appears to be acting on the ball, yet its speed gradually decreases and finally it comes to rest aftersome time. What causes a change in the state of motion of the ball? Is there any force acting on the ball to slow it down that gradually stops it? In which direction must this force be acting? This is the force of friction. The force of friction acting between the surface of the ball and the ground that opposes the motion of the ball, brings the moving ball to rest. The force acting along the two surfaces in contact which opposes the motion of one object over the other is called the force of friction, Frictional force always opposes the motion of the.moving object. This force of friction is due to the roughness of the surfaces of the objects in contact. The more is the roughness of the surfaces in contact, the more is the force of friction between them.

Answer 2

Answer:

Explanation:

The forces in which the two interacting objects are in physical contract in each other