Work And Energy - Practice Test, Class 9 Science


30 Questions MCQ Test | Work And Energy - Practice Test, Class 9 Science


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This mock test of Work And Energy - Practice Test, Class 9 Science for Class 9 helps you for every Class 9 entrance exam. This contains 30 Multiple Choice Questions for Class 9 Work And Energy - Practice Test, Class 9 Science (mcq) to study with solutions a complete question bank. The solved questions answers in this Work And Energy - Practice Test, Class 9 Science quiz give you a good mix of easy questions and tough questions. Class 9 students definitely take this Work And Energy - Practice Test, Class 9 Science exercise for a better result in the exam. You can find other Work And Energy - Practice Test, Class 9 Science extra questions, long questions & short questions for Class 9 on EduRev as well by searching above.
QUESTION: 1

Two objects of masses 1Kg and 3Kg have equal momentum. What is the ratio of their kinetic energies?

Solution:
QUESTION: 2

1.5 kW = ______ watts.

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QUESTION: 3

The other name of Nm is:

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QUESTION: 4
An iron sphere of mass 30 kg has the same diameter as an aluminium sphere whose mass is 10.5 kg. The spheres are dropped simultaneously from a cliff. When they are 10 m from the ground, they have the same _______.  
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QUESTION: 5
Name the physical quantity which is equal to the product of force and velocity.
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QUESTION: 6
A man of mass 50 kg jumps to a height of 1 m. His potential energy at the highest point is (g = 10 m/s2)?
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QUESTION: 7
Which of the following is/are example(s) of Potential Energy ?
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QUESTION: 8
A car is accelerated on a levelled road and attains a velocity 4 times of its initial velocity. In this process the potential energy of the car?
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QUESTION: 9
An iron sphere of mass 10 kg has the same diameter as an aluminium sphere of mass is 3.5 kg. Both spheres are dropped simultaneously from a tower. When they are 10 m above the ground, they have the same?
Solution: Yes, because acceleration of an object due to gravity, when under free fall, is not affected by it's mass as it's equation states and all bodies of varying mass and with same shape and size, fall with the same rate towards the Earth irrespective of their mass.

g=(GM)/R^2
QUESTION: 10

A girl is carrying a school bag of 3 kg mass on her back and moves 200 m on a leveled road. The work done against the gravitational force will be (g =10 m s–2)

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QUESTION: 11
Considering air resistance negligible, the sum of potential and kinetic energies of the free falling body would be:
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QUESTION: 12
Which one of the following is not the unit of energy?
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QUESTION: 13
A light and heavy body have equal momenta. Which one has greater kinetic energy?
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QUESTION: 14
The work done on an object does not depend upon the?
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QUESTION: 15

The type of energy possessed by a simple pendulum, when it is at the mean position is:

Solution:

In a simple pendulum with no friction, mechanical energy is conserved. Total mechanical energy is a combination of kinetic energy and gravitational potential energy. As the pendulum swings back and forth, there is a constant exchange between kinetic energy and gravitational potential energy.

QUESTION: 16

In case of negative work the angle between the force and displacement is:

Solution:

Work done W = F.d cos 0
∴Work done at θ= 0°, W = F.d cos 0°                         (∴cos0° = 1)
 ⇒   W = F.d
For angle θ = 0°,
Work done Is positive, so it is not true.
(b) We know that work done, W = F .d cos 0

For angle 0 = 45°,
work done is positive, so it is not true.
(c) We know that work done, W = d cos θ
Work done at θ = 90°,      W = F.d cos 90°                                      (∴cos 90° = 0)
W = 0
So, it is not true.
(d) Work done at θ = 180°, W = F.d cosθ (∴ cos 180°= -1)
W = - F. d
For negative work, the angle between the force and displacement should be 180°. (/.e„ force and displacement are anti parallel to each other) So, it is true.

QUESTION: 17
An example of Kinetic energy would be: 
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QUESTION: 18
A body of mass 3 kg is dropped from the height of 1m. The kinetic energy of the body will be when it touches the ground. 
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QUESTION: 19
A body is falling from a height h. After it has fallen a height h/2 , it will possess?
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QUESTION: 20
If air resistance is negligible, the sum total of potential and kinetic energies of a freely falling body _______.
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QUESTION: 21
Newton-meter is the SI unit of :
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QUESTION: 22
Which of the following is NOT correct? 
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QUESTION: 23
If the speed of an object is doubled then its kinetic energy is _______.
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QUESTION: 24

How are Joule (J) and ergs (erg) related?

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QUESTION: 25
Water stored in a dam possesses?
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QUESTION: 26
When a body falls freely towards the earth, then its total energy?
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QUESTION: 27
An object of mass 1 kg has potential energy of 1 joule relative to the ground when it is at a height of _______. 
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QUESTION: 28
kWh is the unit of :
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QUESTION: 29

A 1 kg mass has a kinetic energy of 1 joule when its speed is:

Solution:

K.E = 1/2 m v^2
1 = 1/2 * 1 * v^2
2 = v^2
v^2 = 2
v = √2
or
1.4m/s

QUESTION: 30
A 1-kg block is lifted vertically 1m by a boy. The work done by the boy is:
Solution: