Q. 3 A)Answer the following questions
1. What is meant by weight?
2. Explain muscular force with two examples.
3. Why do planets revolve round the sun in definite orbits?
4. What happens when a blacksmith hammers a red hot piece of iron?
Answers
Answer:
The most common definition of weight found in introductory physics textbooks defines weight as the force exerted on a body by gravity. This is often expressed in the formula W = mg, where W is the weight, m the mass of the object, and g is gravitational acceleration.
It is the force applied by the action of muscles of our body from body parts like arms and leg. Kicking a ball, Lifting a weight, and Walking , running, jumping etc.
Newton realized that the reason the planets orbit the Sun is related to why objects fall to Earth when we drop them. The Sun's gravity pulls on the planets, just as Earth's gravity pulls down anything that is not held up by some other force and keeps you and me on the ground.
A blacksmith first heats a piece of iron till it becomes red hot. It then becomes soft and can be beaten into desired shape. Iron when heated and beaten it forms some shape and it becomes in its liquid form.
Answer:
1.The force which is exerted by a body by gravity is known as weight.
2. the force which is exerted by the force of muscle is known as muscular force.
Example:lifting,kicking.
4. A blacksmith first heats a piece of iron till it becomes red hot. It then becomes soft and can be beaten into desired shape. Iron when heated and beaten it forms some shape and again heated it regain initial iron. Thus, this change is a reversible change.