WORK AND ENERGY

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Created on By buzzerkings

Work and Energy

1 / 79

The area under force displacement graph gives us: -

2 / 79

Which of the following force is non-conservative force?

3 / 79

When the speed of your car is halved, by what factor does its kinetic energy

decreases?

4 / 79

A 1.75 m heighted weight-lifter raises weights with a mass of 50 kg to a height of 5m above his head. How much work is being done by him? (g=10ms?)

5 / 79

Which of the following statement shows that no work is done? 

6 / 79

An automobile is moving forwards with uniform velocity due to the force exerted by its engine. If that force is double with the velocity remaining constant what happens to its total power?

7 / 79

A man carries a 1 kg body 10m horizontally on a level ground. The work done by the man is: 

8 / 79

A man has a mass of 80 kg. He ties himself to one end of rope which passes over a single fixed pulley. He pulls on the other end of the rope to lift himself up at an average speed of 50cms. What is the average useful power at which he is working? 

9 / 79

The rate at which work is being done is called:

10 / 79

 A stone of mass 2.0 kg is dropped from a rest position 5.0m above the ground. What is its velocity at a height of 3.0m above the ground? 

11 / 79

 Energy consumed by 60-watt bulb in 2 minutes is equal to

12 / 79

Two boys weighing in the ratio 4:5 goes up stair taking time in the ratio 5:4. The ratio their power is:

13 / 79

An engine pumps out 40 kg of water in one second. The water comes out vertically upwards with a velocity of 3ms', the power of engine in kilowatt is:

14 / 79

When a force retards the motion of a body the work done is:

15 / 79

A man of mass 60 kg climbs up a 20m long staircase to the top of a building 10m high What is the work done by him: Take g 10ms-2

16 / 79

Which one of the following is a greater work?

17 / 79

At what angle work done will be maximum?

18 / 79

 If mass 'm' is dropped from height 'h' vertically, f is the force of friction during downward motion and 'v' is the velocity at bottom, following equation will be hold: 

19 / 79

Work done will be zero if angle between Force and displacement is:

20 / 79

 Potential energy per unit volume is given by

21 / 79

 A 6.0 kg block is released from rest 80m above the ground. When it has falien 60m its kinetic energy is approximately:

22 / 79

The gravitational potential energy per unit mass is called:

23 / 79

The heat energy dissipated by 40 watt also in one hour is 

24 / 79

 If velocity is double, then.

25 / 79

Which one of the following is a non-conservative force?

26 / 79

The consumption of energy by 60-watt bulb in 2 seconds is:

27 / 79

If a certain force acts on an object and changes its kinetic energy from 65 J to 130 J, then work done by the force will be: 

28 / 79

Work done on a body equals change in its___ energy. 

29 / 79

100 joules work has been done by an agency in 10 seconds. What is power of agency?

30 / 79

A.force 2i+j has moved its point of application from (2,3) to (6,5). What Is work done?

31 / 79

 Mathematical form of work energy principle is

32 / 79

The work energy principle is valid for

33 / 79

The amount of work required to stop a moving object is equal to:

34 / 79

 If a certain force acts on an object and changes its kinetic energy from 65 J to 130 J, then work done by the force will be:

35 / 79

Work done on a body equals change in its _____energy.

36 / 79

An engine pulls a car of mass 1500 kg on a level road at a constant speed of 5 ms-1. If the frictional force is 500 N, what power does the engine generate?

37 / 79

 The power needed to lift a mass of 5000g to height of 1 m in 2 second is

38 / 79

An elevator's motor produces 3000 W power. The speed with which it can lift a 1000 kg load is:

39 / 79

An engine pumps out 40 kg of water in one second. The water comes out vertically upwards with a velocity of 3 m s-1. What is the power of engine in kilowatt?

40 / 79

An engine pumps up 100 kg of water through a height of 10 m in 5s. Given that the efficiency of the engine is 60%, what is the power of the engine? (Take g = 10 ms-2)

41 / 79

 A man M1 of mass 80 kg runs up a staircase in 15 s. Another man M2 also of mass 80 kg runs up the same staircase in 20 s. The ratio of the power developed by them will be:

42 / 79

The power output of a lamp is 6W. How much energy does the lamp give out in 2 minutes? 

43 / 79

A force of 1000 N is needed to lift the hook of a crane at a steady velocity. The crane is then used to lift a load of mass 1000 kg at a velocity of 0.50ms-1. How much of the power developed by the motor of the crane is used in lifting the hook and the lond? (Take g as 10ms-2).

44 / 79

To travel at a constant speed, a car engine provides 24 kW of useful power. The driving force on the car is 600 N. At what speed does it travel?

45 / 79

The time taken by an engine of power 10 kW to lift a mass of 200 kg to the height of 40 m is

46 / 79

 A 500N force is applied on an object and it moves with velocity 10ms-1. If value of power is 2500 watt. Then what will be the angle between force and displacement 

47 / 79

100 joules work has been done by an agency in 10 seconds. What is power of agency?

48 / 79

The consumption of energy by 60-watt bulb in 2 seconds is:

49 / 79

 Energy consumed by 60-watt bulb in 2 minutes is equal to

50 / 79

A stone is thrown up from the surface of earth when it reaches at maximum height. Its total energy is equal to

51 / 79

Energy stored in the spring of watch is

52 / 79

A body is falling from a height h. After it has fallen a height h/2, it will possess

53 / 79

Potential energy per unit volume is given by

54 / 79

 A truck and a car are moving with equal velocity. On applying brakes, both will stop after a certain distance, then?

55 / 79

When force and displacement are in the same direction, the kinetic energy of the body

56 / 79

The kinetic energy acquired by a body of mass m is travelling some distance s, starting from rest under the actions of a constant force, is directly proportional to

57 / 79

 A bomb of mass 30 kg at rest explodes into two pieces of masses 18 kg and 12 kg. The velocity of 18 kg mass is 6 m s-1. The K.E of other mass is

58 / 79

 A ball of mass 2 kg and another of mass 4 kg are dropped together from a 60 feet tall building. After a fall of 30 feet each towards earth, their respective kinetic energies will  be in the ratio of:

59 / 79

 Car X is traveling at half the speed of car Y. Car X has twice mass of car Y. Which statement is correct? 

60 / 79

Kinetic energy of a body moving with speed of 10 m s is 30 J. If its speed becomes 30m/s its K.E will be

61 / 79

The momentum and kinetic energy of a ball is numerically equal. The numerical value of velocity is

62 / 79

If momentum of a moving object is doubled then its kinetic energy will be

63 / 79

The Bodies of one kg and four kg have same kinetic energy. The ratio in their momenta will be

64 / 79

What will be the ratio of kinetic energies of alpha particle and proton if

their linear momentum will be same

65 / 79

 If velocity is double, then.

66 / 79

A gardener pushes a lawn roller through a distance of 20m. If he applies a force of 20kg weight in a direction inclined at 60° to the ground, find the work done by him. (g=9.8m/s²)

67 / 79

A person is holding a bucket by applying a force of 10N. He moves a horizontal distance of 5m and then climbs up a vertical distance of 10m. Find the total work done by him? 

68 / 79

 If force and displacement of particle in direction of force are doubled. Work would be

69 / 79

 A person holds a bucket of weight 60 N. He walks 7 m along the horizontal path and then climbs up a vertical distance of 5 m. The work done by the gravity is:

70 / 79

A body travels displacement of 10 m by force of 5 N If work done is 25 J then angle between F and vector d is

71 / 79

A force of 3i+ 2j+ 4k N gives displacement of 10ĵ m. The work done is

72 / 79

A person walks 2 m with an acceleration of 5 m s2, holding object of mass 2 kg.  The net work done on the object is 

73 / 79

 If a mass of 5 Kg is lifted upto 5m height, what will be the work done against the gravitational field

74 / 79

 At what angle the work done will be half of its maximum value

75 / 79

A force 2i + j has moved its point of application from (2,3) to (6,5). What is work done?

76 / 79

Work done will be zero if angle between Force and displacement is:

77 / 79

 Which one of the following is a greater work?

78 / 79

At what angle work done will be maximum?

79 / 79

If the momentum of a body decreases by 20% the percentage decreases in K.E will be:

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