Question

1 What is Friction?
2 What is Muscular Force? Give examples
3 We see lightning first and hear thunder. Why?​

Answer 1

Answer:

1. Friction is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
2. It is a force that results because of the action of muscles and is a contact force since there is contact between the surfaces. Muscular force is required whenever the movement of the body occurs.

The force applied by the action of muscles in our body is termed as a muscular force. For example, when you pick up a book placed on the table using your hands, you apply muscular force. It is the force that is exerted by the Earth on every object, which is near or on its surface

3.If we are watching the sky, we see the lightning before we hear the thunder. That is because light travels much faster than sound waves. ... It takes approximately 5 seconds for the sound to travel 1 mile. If the thunder follows the lightning almost instantly, you know the lightning is too close for comfort!

Answer 2

Explanation:

1) Friction is the force which opposes motion.

2) The physical force applied by our muscle is muscular force. Example- Pushing a trolley.

3) We see lightning first and then hear it because light is much faster then sound.