Class 9th Physics Unit 6 Work and Energy

physics 9th notes Chapter No 6

1. Which unit is equal to kgm²s⁻² in the units given below?

 
 
 
 

2. Energy is quantity:

 
 
 
 

3. Work done will be zero if displacement is—–to force:

 
 
 
 

4. Decrease in kinetic energy is equal to:

 
 
 
 

5. What will be the kinetic energy of a car of mass 1000 kg moving with a velocity of 20 ms⁻¹?

 
 
 
 

6. Total energy of the system:

 
 
 
 

7. Ability of a body to do work due to its height from the surface of earth is called energy:

 
 
 
 

8. What is efficiency of solar cell?

 
 
 
 

9. Energy possessed by a body due to its motion is called?

 
 
 
 

10. A motor lift a weight of 5N up to the height of 2m in 4s. What will be the power of the motor?

 
 
 
 

11. Ability of a body to do work due to its position is called:

 
 
 
 

12. What will be the magnitude of work if a force of 25 N pulls a stone through a distance of 5 m in its direction?

 
 
 
 

13. How much power is used by a 40 kg athlete by climbing 10m high ladder in 10 s:

 
 
 
 

14. A bowler during playing cricket throws a ball of mass 200 g with a velocity of 20 ms⁻¹. Its kinetic energy will be:

 
 
 
 

15. What is efficiency of Petrol engine?

 
 
 
 

16. There are ___ basic kinds of energy:

 
 
 
 

17. Work done will be _____ if no force act on the body:

 
 
 
 

18. What will be efficiency if input is 100 g and output is 55 j?

 
 
 
 

19. 1120 watts are equal to

 
 
 
 

20. Work done will be one____if a force of one Newton acts on the body and it covers the distance of 1 meter in the direction of force:

 
 
 
 

21. What is efficiency of electric motor?

 
 
 
 

22. For movement of our body energy is used:

 
 
 
 

23. For work ___ conditions should be fulfilled:

 
 
 
 

24. Basic kinds of mechanical energy:

 
 
 
 

25. Energy of the water stored in the dam is: 

 
 
 
 

26. When a ball is lifted to a height `11′ from the ground, it will possess energy:

 
 
 
 

27. For the propagation of signals in our body energy is used:

 
 
 
 

28. For maintaining the body temperature energy is used:

 
 
 
 

29. What will be the power of a machine doing 10 J work in 5 seconds?

 
 
 
 

30. Unit of power is:

 
 
 
 

31. Work done will be maximum if displacement is —– to force:

 
 
 
 

32. How many types of mechanical energy are?

 
 
 
 

33. Unit of work is:

 
 
 
 

34. Energy possessed by a ball when it is lifted to a height ‘h’ from the ground:

 
 
 
 

35. Rate of doing work with respect to time is known as:

 
 
 
 

36. Unit of Energy in System International is

 
 
 
 

37. What will be the kinetic energy of a body if its velocity is doubled? 

 
 
 
 

38. Decrease in potential energy is equal to:

 
 
 
 

39. Product of force and distance covered in the direction of force is:

 
 
 
 

40. 1 hp =

 
 
 
 

41. One Mega Joule is equal to:

 
 
 
 

42. What is efficiency of electric fan?

 
 
 
 

43. What is young modulus of Aluminum?

 
 
 
 

44. Work is quantity:

 
 
 
 

45. What will be the kinetic energy of a body if its mass is doubled?

 
 
 
 

Short Questions

A crate is moved by pulling the rope attached to it. It moves 10 m on a straight horizontal road by a force of 100 N. How much work will be done if?
The rope is parallel to the road
The rope is making an angle of 30 with the road.
Define Elastic Potential Energy.
Define Energy and write down its unit.
Define energy, give two types of mechanical energy.
Define Gravitational Potential Energy.
Define the ideal system. Why is it not possible to construct 100 percent efficient system?
Define work. What is its SI unit?
Describe electrical energy with examples?
Describe heat energy with examples?
Describe light energy with examples?
Describe mechanical energy with examples?
Describe nuclear energy with examples?
Describe sound energy with examples?
Describe the harmful waste products released by fossil fuels?
Describe the process by which energy is converted from one form to another concerning fossil fuel energy?
Describe the process of electricity generated by biomass?
Describe the process of electricity generated by geothermal energy?
Describe the process of electricity generated by solar cells?
Describe the process of electricity generated by wind energy?
Describe the processes by which energy is converted from one form to another concerning nuclear fuels?
How can you find the efficiency of a system?
How energy is obtained from the sun?
How energy is obtained from water?
How much power is used by a 40 kg athlete by climbing 10m high ladder in 10s?
List non-renewable sources of energy?
List the environmental issues associated with nuclear fuels?
Name a device that converts mechanical energy into electrical energy.
Name five devices that convert electrical energy into mechanical energy.
State mass-energy equation E = mc².
The kinetic energy of a body of mass 2 kg is 25 J. What will be its speed?
What is Efficiency? Write its formula and unit (if any)
What is meant by the efficiency of a system?
What is meant by the term power?
What is Power? Write down its unit and Define it.
When does a force do work? Explain.
Which form of energy is most preferred and why?
Why do we need energy?
Why fossil fuels are called non-renewable form of energy?

Long Questions

 

A 500 g stone is thrown up with a velocity of 15 ms⁻¹. Find its
(i) Potential Energy at its maximum height
(ii) Kinetic Energy when it hits the ground
A 50 kg man moved 25 steps up in 20 seconds. Find his power, if each step is 16 cm high.
A block weighing 20 N is lifted 6 m vertically upward. Calculate the potential energy stored in it.
A car weighing 12 k N has a speed of 20 ms⁻¹. Find its kinetic energy.
A man has pulled a cart through 35 m applying a force of 300 N. Find the work done by the man.
A man pulls a block with a force of 300 N through 50 m in 60 s. Find the power used by him to pull the block.
An electric motor of 1hp is used to run water pump. The water pump takes 10 minutes to fill an overhead tank. The tank has a capacity of 800 liters and height of 15 m. Find the actual work done by the electric motor to fill the tank. Also find the efficiency of the system. (Density of water = 1000 kgm⁻³ )  (Mass of 1 liter of water = 1 kg)
Calculate the power of a pump which can lift 200 kg of water through a height of 6 m in 10 seconds.
Define Gravitational Potential Energy and derive its mathematical formula.
Define Kinetic Energy and derive its relation.
Define kinetic energy and derive its mathematical formula
Define potential energy and derive its relation.
Define work. Derive its mathematical formula.
Derive the relation for work done by a force inclined with the displacement?
Differentiate energy resources as renewable and non-renewable resources of energy with examples of each?
Draw the Flow Diagram Of An Energy Converter.
Explain by drawing flow diagram electricity from fossil fuels.
Explain different Forms of Energy.
Explain Mass — Energy Equation.
Explain Renewable Energy Sources.
Explain Solar House Heating.
Explain the effect of consumption of Energy on Environment.
Explain the electricity from fossil fuels with block diagram.
Explain the functioning of the solar house heating system?
How is energy converted from one form to another? Explain.
List major sources of energy?
List the different forms of energy with examples?
List the environmental issues associated with energy. Highlight the solution to these issues?
On reaching the top of a slope 6 m high from its bottom, a cyclist has a speed of 1.5 ms⁻¹. Find the kinetic energy and the potential energy of the cyclist. The mass of the cyclist and his bicycle is 40 kg.
Prove that Kinetic Energy =   1/2 m v².
What are the future hopes of the world about energy?
What is Efficiency? Explain the ideal machine and practical systems.
What is Power? Write down its unit and Define it.

Leave a Reply

Your email address will not be published. Required fields are marked *