Practice Section 2 question answer - general science mcq Online Quiz (set-1) For All Competitive Exams
Q-1) In case of negative work the angle between the force and displacement is
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Q-2) When a stone tied to a string is whirled in a circle, the work done on it by the string is
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Q-3) Which one of the following is a vector quantity?
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Q-4) Consider an elevator moving downwards with an acceleration a, the force exerted by a passenger of mass m on the floor of the elevator is
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Q-5) When a satellite is in the synchronous orbit above the equator, it stays in one place with reference to the earth by making each revolution in just the same time as it takes the earth to rotate once. What is the altitude of the synchronous orbit?
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The period of revolution of the satellite must be exactly one day, or 86400s. The centripetal acceleration of the satellite must be $4π^2/T^2$ , the gravitational field must be
g = $g_0 (r_0/r)^2$. In free fall, a = g, so
$r=^3√{{(9.8m/{s}^2)(6.4×{10}^{-6}m)^2(86400s)^2}/{4π^2}}$
= 4.23 × $10^7$m
To get the altitude, subtract the radius of the earth. The satellite must be at an altitude of 36000 km.
Q-6) A man jumped at a speed of 5 metre per second from a stationary boat and the boat moved off with the speed of 0.5 metre per second. How many times is the mass of the boat greater than that of the man?
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Q-7) The potential energy is always the same for an object with the same
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Q-8) Consider the following statements :
- The objects appear to be more heavy when submerged in water than they are in air.
- A needle place carefully on the surface of water may float, whereas a ball of the same material will always sink.
Which of these statements is/are correct ?
(a)
(b)
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Buoyancy is an upward force exerted by a liquid, gas or other fluid, that opposes the weight of an immersed object.
Q-9) A passenger in a moving train tosses a coin. If the coin falls behind him, the train must be moving with
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Q-10) The working principle of a washing machine is
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