Answer:
149.8Hz
Explanation:
V=I.(XL).........{1}
where (XL) is inductive reactance
(XL) =2πfL......... {2}
V= 41.5, l= 4.5, L= 9.8* 10^-³
take π to be 3.14
(XL) = V/I
= 41.5/4.5
= 9.22
f = (XL) /2πL
= 9.22* 10^³/6.28* 9.8
=149.8
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This is the reason why dimensional analysis is very important. It is a technique used that only involves operations with units. You disregard the quantities first. The concept is to make sure that the final answer of your calculations must be consistent of what is asked. Similar units are cancelled when they appear both on the numerator and denominator side. If the mathematicians used this, they could've prevented the crash from happening. What good would the calculations bring if you are not consistent with the units?
We have: K.E. = mv² / 2
here, m = 4 Kg
v = 9 m/s
Substitute their values into the expression:
K.E. = (4)(9)² / 2
K.E. = (4)(81) / 2
K.E. = 324 / 2
K.E. = 162 Joules
In short, Your Answer would be 162 J
Hope this helps!
Answer:
The correct answer is d
Explanation:
In this exercise they ask us which statement is correct, for this we plan the solution of the problem, this is a Doppler effect problem, it is the frequency change due to the relative speed between the emitter and the receiver of sound.
The expression for the Doppler effect of a moving source is
f ’= (v / (v- + v_s) f
From this expression we see that if the speed the sound source is different from zero feels a change in the frequency.
The correct answer is d
