The idea that the Earth sits motionless in the Universe at the center of a revolving globe of stars, with the Moon and planets i
1 answer:
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<h2>Answer:</h2>
<em><u>(a). 16.741 m/s</u></em>
<em><u>(b). 15.75 m/s</u></em>
<h2>Explanation:</h2>In the question,
Height of the cliff, h = 37 m
Time taken to reach the sound to us = 2.92 s
Speed of the sound in air at room temperature = 343 m/s
Now,
Let us say the speed of the ball = u m/s
So,
Time taken by the ball to reach at the bottom, t is given by,
So,
Splash is heard after = 2.92 s
So,
<u>Time taken by sound to travel the shortest distance along the hypotenuse of the triangle</u> thus formed is,
t = 2.92 - 2.747
t = 0.172 s
Now,
Distance traveled by sound is given by,
So,
In the triangle using the Pythagoras Theorem,
Horizontal distance traveled is,
So,
Speed of throwing of ball is given by,
<em><u>Therefore, the speed of the ball = 16.741 m/s.</u></em>
(b).
If,
Speed of sound = 331 m/s
So,
<u>Distance traveled by sound</u> is,
So,
Distance traveled in the horizontal by ball is,
So,
Speed of the ball thrown is given by,
<em><u>Therefore, the speed of the ball = 15.75 m/s.</u></em>
Answer:
D. The period would decrease by sqrt (2)
Explanation:
The period of a mass-spring system is given by:
where
m is the mass
k is the spring constant of the spring
If the spring constant is doubled,
k' = 2k
So the new period will be
So the correct answer is
D. The period would decrease by sqrt (2)
An electric motor has an effective resistance of 29. 4 ω and an inductive reactance of 42. 6 ω. When working under load. the rms voltage across the alternating source is 442 v. The rms current will be 8.54 A
AC stands for “Alternating Current,” meaning voltage or current that changes polarity or direction, respectively, over time. AC electromechanical generators, known as alternators, are of simpler construction than DC electromechanical generators.
RMS or root mean square current/voltage of the alternating current/voltage represents the D.C current/voltage that dissipates the same amount of power as the average power dissipated by the alternating current/voltage. For sinusoidal oscillations, the RMS value equals peak value divided by the square root of 2.
I (RMS) = RMS voltage /
= 442 /
= 442 /
= 442 /
= 8.54 A
To learn more about Alternating Current here
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