mechanics (mass, force, acceleration, work, energy, momentum, velocity) - Category wise Question and Answer Practice Test with Solutions
mechanics (mass, force, acceleration, work, energy, momentum, velocity) PRACTICE TEST [5 - EXERCISES]
set 1
set 2
set 3
set 4
set 5
Question : 21
A person sitting on a chair in a satellite feels weightless because
a) the normal force is zero
b) the normal force by the chair on the person balances the earth’s attraction
c) the earth does not attract the objects in a satellite
d) the person in satellite is not accelerated
Answer »Answer: (a)
The weightlessness inside a satellite is due to the fact that the surface does not exert any force on the body and hence its apparent weight is zero.
Question : 24
Consider the following statements: A simple pendulum is set into oscillation. Then:
- the acceleration is zero when the bob passes through the mean position.
- in each cycle, the bob attains a given velocity twice.
- both acceleration and velocity of the bob are zero when it reaches its extreme position during the oscillation.
- the amplitude of oscillation of the simple pendulum decreases with time.
a) 1, 2 and 4
b) 1 and 2
c) 3 and 4
d) 2, 3 and 4
Answer »Answer: (a)
The bob of a simple pendulum is attached to a string which pulls the bob along its length.
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Here B and C are extreme positions whereas A is the mean position. The speed of the bob increases as it approaches the mean position A and continues to move till it reaches C.
At C the speed becomes zero. Due to the unbalanced force, the bob moves towards the mean position. The speed of the bob is maximum at the mean position and is zero at the extreme positions.
Thus, it is clear that in each cycle bob velocity increases from zero to maximum. This means that it attains a given velocity twice.
Suppose the bob of the pendulum reaches up to B while oscillating, then AB is the amplitude. For the next oscillation, the bob fails to reach B but it will reverse the direction from point B′ instead of B. The amplitude of oscillation in the second case is AB′ which is less than AB.
That means a retarding force is acting on the bob thereby reducing the amplitude of oscillation. This retarding force is nothing but air resistance or air friction. At an extreme position, acceleration is maximum.
So statement 3 is not correct.
IMPORTANT general science mcq EXERCISES
set 1 Online Quiz
Click to Start..general science mcq CATEGORIES
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» Measurement And SI Units
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» Measuring Devices And Scales
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» Mechanics (Mass, Force, Acceleration, Work, Energy, Momentum, Velocity)
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» Force Of Gravity, Solids And Fluids
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» Motion Under Gravity
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» Physical Properties Of Materials
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» Light, Heat, Thermodynamics, Wave Motion, Sound, Optics & Oscillations
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» Electric Current And Magnetism
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» Nuclear Physics And Conductivity
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» Modern And Space Physics, Sources Of Energy
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» General Concepts Of Chemistry
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» Nature Of Matter And Composition
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» Atomic Structure Molecules And Nuclear Chemistry
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» Classification Of Elements, Chemical Bonding, Periodicity In Properties & Physical Transformation
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» Metals, Non Metals, Minerals, Ores, Properties, Uses
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» Alloys, Carbon & Its Various Forms, Hydrogen & Compounds, Sulphur, Nitrogen, Halogen & Inert Gases
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» Acids, Bases, Salts And Metals
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» Hydrocarbon, Alcohol, Polymer, Organic Acid And Explosive Substance
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» Fuel, Food Preservation, Nutrition, Medicine, Detergents And Fertilizers
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» Inorganic Chemistry
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» Organic Chemistry
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» Environmental Chemistry
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» Some Important Man Made Materials
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» Sub Divisions Of Biology
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» Genetics, Evolution Of Life & Ecological Biodiversity
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» Taxonomy
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» Heredity
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» Biofertilizer
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» Biological Classification Cell Tissues And Division
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» Human Anatomy
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» Blood Transport System
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» Digestion And Excretion
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» Photosynthesis
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» Vitamins, Nutrition, Health, Disease And Treatment
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» Endocrine Glands, Hormones
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» Physiology Of Plants, Humans And Animals
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» Reproduction
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» Genetic Engineering And Bio Technology
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