- An electric motor rotating at an angular speed of 600 rpm starts to slow down when the current is interrupted, and its angular speed reaches 150 rpm in 3 seconds. How many revolutions does it make from start to stop?   A) 20 cycles B) 5 cycles C) 25 cycles D) 15 cycles E) 10 cycles

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Q: Suppose that à = 2i + j, B =i- 4j + k, and =j+k. What is A· (B x Č), A) -2 k B) -11 -2 D) -11 k

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Q: Same situation as in the previous two problems this time the magnet s mass is 3.54 kg and the…

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Q: The drawing shows a bar magnet falling through a metal ring. In i, the ring is solid all the way…

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Q: Why does an electric fan continue to rotate for some time after the current is switched off?

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Q: Same situation as in the previous two problems this time the magnet s mass is 4.19 kg and the…

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Q: The slip of the induction motor depends on the rotor speed of the machine.  Select one: True False

A: True

Q: What two kinds of rotational motion are exhibited by electron in an atom?

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Q: There are 2 thin uniform rods. Rod DC is pinned at its center of gravity (free to rotate 360…

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Q: If a bar magnet of magnetic moment M is bent as shown in diagram, then the new moment of system…

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Q: 8) Which of the following has the same units as the farad? A) N's (B) Ns' (C)Ns (D) Ns²

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Q: Define a kilowatt hour. How is it related to joule?

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Q: The blades of fan continue to rotate even when the current is switched off?

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Q: An electric motor rotating at an angular speed of 600 rpm starts to slow down when the current is…

A: Given  Initial angular speed ωi=600×2π60=62.8 rad/s after 3 sec ωf=150×2π60=15.7 rad/s

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Proper Length

The theory of special relativity explains the connection between space and time to objects that move in a straight line at a constant speed. The objects move at the speed of light. When an object approaches light speed, its mass is endless and cannot move faster than light. The most crucial postulate of Einstein's special relativity is that the laws of nature do not change in each frame of reference.