E. Short answer questions.
1. Define work with an example,
2. Give an example of a situation where you are applying force, but work is still not
done.
3. The work is said to be done under what circumstances?
4. What are energy-giving foods? Give any five examples of it
5. Write the names of any five types of energy.
F. Long answer questions,
1. With the help of suitable examples, discuss when work is done, and when not,
2. What is the difference between work and energy? Explain with an example,
3. How can we say that the amount of energy we need depends on the task that we
are doing?
4. Differentiate between renewable and non-renewable energy.
120
Answers
Answer:
Here Are Your Answers
Explanation:
E.
1) Work is force applied over distance. Examples of work include lifting an object against the Earth's gravitation, driving a car up a hill, and pulling down a captive helium balloon. Work is a mechanical manifestation of energy. The standard unit of work is the joule (J),
2)If there is no motion in the direction of the force, then no work is done by that force. Yet you certainly feel like you are doing work if you carry a heavy box. ... It changes the direction of the motion, but it does no work on the object. This can be applied to any circular orbit.
3)In summary, work is done when a force acts upon an object to cause a displacement. Three quantities must be known in order to calculate the amount of work. Those three quantities are force, displacement and the angle between the force and the displacement.
4)Food that give us energy is known as energy giving food.
example:
fatty fish
brown rice
eggs
coffee
apple
5) Sound Energy, Chemical Energy, Radiant Energy, Electric Energy, Atomic Engery and Mechanical Energy.
F.
1)POSITIVE WORK :the work done on an object is said to be positive work when force and displacement are in same direction.
example: When an object moves on horizontal surface,force and displacement acts in forward direction. So,work done is positive.
NEGATIVE WORK:The work done is said to be negative work when force and displacement are in opposite direction.
example: When an object is thrown upwards,the force CTS in downward direction whereas displacement acts in upward direction.
ZERO WORK:The work done is said to be zero work when force and displacement are perpendicular to each other or when either force or displacement is zero.
example: When we hold an object and walk,the force acts in downward direction whereas displacement acts in forward direction
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