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Free download in PDF Power and Energy Short Questions & Answers for competitive exams. These objective type questions are very important for competitive exams like IIT-JEE, NEET, AIIMS, JIPMER etc. These short solved questions or quizzes are provided by Gkseries.
41
An external force is being applied on an object at some angle and it causes the object either to be pulled or pushed on a rough surface. Which of the following holds true ?
[A]
It is easier to push the object
[B]
It is easier to pull the object
[C]
It requires same efforts to push or pull the object
[D]
None of the above
Answer: It is easier to pull the object
42
A car with mass ‘M’ is moving on horizontal road with velocity ‘v’. Driver applies accelerator and increases it speed 3 times to ‘3v’. The final K.E. acquired by the car will be :
[A]
1.5 Mv2
[B]
2.5 Mv2
[C]
3.5 Mv2
[D]
4.5 Mv2
43
As per the statement of Q.9, the amount of addition work done by the car, after applying the accelerator, is
[A]
1.5 Mv2
[B]
2.5 Mv2
[C]
3.5 Mv2
[D]
4 Mv2
44
In first case, a force of 5 N is applied on a object for 6 minutes and displaces it by 10 meters. In second case, A force of 10 N is applied on the same object for 3 minutes and displaces it by 5 meters. In which case there is more work done?
[A]
First case
[B]
Second case
[C]
In both cases, work done is same
[D]
In both cases, work done is zero
Answer: In both cases, work done is same
45
The person will have maximum Potential Energy, when ?
[A]
he is sleeping on the ground
[B]
he is sitting on the ground
[C]
he is sleeping on the bed
[D]
he is standing on the roof
Answer: he is standing on the roof
46
Expression for Power of an object is equal to:
[A]
Power = Work done X Time
[B]
Power = Time/ Work done
[C]
Power = Work done/Time
[D]
Power = Force X Displacement
Answer: Power = Work done/Time
47
When a body falls freely towards the earth then the total energy
[A]
remains constant
[B]
increases
[C]
decreases
[D]
first increases and then decreases
48
In hydro electricity generation, water stored in a dam possesses:
[A]
electrical energy
[B]
chemical energy
[C]
thermal energy
[D]
potential energy
49
When a body slides down on an inclined surface, which holds true ?
[A]
It has no energy
[B]
It has potential energy only
[C]
It has kinetic energy only
[D]
It has both kinetic and potential energy
Answer: It has both kinetic and potential energy
50
1 J is the amount of work done on an object when a force of 1 N displaces it along its line of action by :
[A]
1 cm
[B]
1 m
[C]
100 m
[D]
1 km
51
As a person climbs up from ground floor of the building to higher floor, The potential energy of person on the higher floor, relative to the ground floor, can be expressed as
[A]
the work done in lifting his weight from ground floor to higher floor
[B]
the product of his weight and the distance between the ground and higher floor
[C]
the energy the person because of his position above the ground floor
[D]
Any one of the above
Answer: Any one of the above
52
According to standard definition of Work done, when the force 'F' acts on the object and object is displaced through a distance 's' in the direction of the force, then work done by a force is equal to
[A]
W = F/s
[B]
W = s/F
[C]
W = F × s
[D]
W = Zero
53
According to the law of conservation of energy,
[A]
Energy can only be transformed from one form to another
[B]
It can neither be created nor destroyed
[C]
The total energy before and after the transformation always remains constant
[D]
All of the above
54
Newton meter per second or 1 joule/second or 1 watt is unit of
[A]
Force
[B]
Work
[C]
Power
[D]
Energy
55
For an object of mass 'm', falling freely from height 'h', under acceleration due to gravity 'g', If v is the velocity of the object at a given instant, then during the course of its fall, for all points, which of the expression given below is correct ?
[A]
mgh > 1/2 mv2
[B]
mgh < 1/2 mv2
[C]
mgh = 1/2 mv2
[D]
mgh + 1/2 mv2 = Constant
Answer: mgh + 1/2 mv2 = Constant
56
A vector quantity has both magnitude as well as direction, where as a scalar quantity has only magnitude and no direction. which of the given below is a scalar quantity?
[A]
Velocity
[B]
Force
[C]
Work done
[D]
Momentum
57
In a construction site, a crane lifts 1000 kg of concrete mix to roof top at a height of 20 meters in 50 seconds. If the value of gravity 'g' due to earth is 10 m s-2, the power of elevator will be..
[A]
2 KW
[B]
3 KW
[C]
4 KW
[D]
5 KW
58
An object is thrown vertically upward and it reaches to a maximum height 'h' from the ground. During its flight, on reaching 3/4 of height H, it will acquire?
[A]
less potential and high kinetic energy
[B]
more potential and less kinetic energy
[C]
same potential and kinetic energy
[D]
only kinetic energy
Answer: more potential and less kinetic energy
59
An object is subjected to free fall from height 'h' to ground. At mid point of its fall i.e. at 1/2 of height H, it will acquire?
[A]
more kinetic and less potential energy
[B]
less kinetic and more potential energy
[C]
same kinetic and potential energy
[D]
only potential energy
Answer: same kinetic and potential energy
60
An object is displaced by 10 meters in the direction of applied force. If the applied force is 75 N, What is the work done by the force?
[A]
0.75 Joule
[B]
7.5 Joule
[C]
75 joule
[D]
750 joule
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