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3 years ago

Which three elements have strong magnetic properties?

Physics

2 answers:

kotykmax [81]3 years ago

5 0

The answer is A. This your answer

lara [203]3 years ago

3 0

Answer is A. Iron cobalt nickel

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Why time does not flow backwards ?

MaRussiya [10]

it is B and i cant explain sadly because i dont even know why time doesnt flow backwards even though that would be cool. please mark brainiest

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3 years ago

Two rooms are in contact. One is at 15°C and the other at 21°C. Choose the best statement concerning the heat flow.

amid [387]

A is the answer to your question

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4 years ago

Read 2 more answers

The motors that drive airplane propellers are, in some cases, tuned by using beats. The whirring motor produces a sound wave hav

sweet-ann [11.9K]

Answer:

A) 2 possible frequencies of second propellar = 424 rpm or 724 rpm

B) Correct frequency is f2 = 724 rpm

C) Reason is stated in explanation

Explanation:

A) We are given;

Frequency of first propeller; f1 = 574 rpm

Beat frequency; f_beat = 2.5 Hz = 2.5 × 60 rpm = 150 rpm

Now, formula for the beat frequency is;

f_beat = |f1 - f2|

Now, |f1 - f2| means it is inside an absolute value.

Thus, it means,

f1 - f2 = 150 or f2 - f1 = 150

Thus;

574 - f2 = 150

Or f2 - 574 = 150

So,f2 = 574 - 150 = 424 rpm or f2 = 574 + 150 = 724 rpm

2 possible frequencies of second propellar = 424 rpm or 724 rpm

B) Now, if we increase the speed of the second propellar slightly, it means that f2 will increase as well.

Now, from the 2 possible values of f2 gotten, we can see that for f1 - f2 = 150, when we increase f2, the beat frequency will reduce while for f2 - f1 = 150, when we increase f2, the beat frequency will increase.

Thus, it's the frequency of f2 gotten in f2 - f1 = 150 that is the correct answer.

Thus, when we increase the speed of the second propellar slightly, it means that;

f2 = 724 rpm

C) Answer in part B is correct because as we increase the speed of the second propellar, the frequency will also increase and the value of f2 that corresponds with an increase in speed is 724 rpm.

7 0

4 years ago

CAN SOMEONE PLEASE HELP ME WITH MY PHYSICS QUESTIONS? I NEED CORRECT ANSWERS ONLY!

BARSIC [14]

<h2>Right answer: acceleration due to gravity is always the same </h2><h2 />

According to the experiments done and currently verified, in vacuum (this means there is not air or any fluid), all objects in free fall experience the same acceleration, which is the acceleration of gravity.

Now, in this case we are on Earth, so the gravity value is $9.8\frac{m}{s^{2}}$

Note the objects experience the acceleration of gravity regardless of their mass.

Nevertheless, on Earth we have air, hence air resistance, so the afirmation "Free fall is a situation in which the only force acting upon an object is gravity" is not completely true on Earth, unless the following condition is fulfiled:

If the air resistance is too small that we can approximate it to zero in the calculations, then in free fall the objects will accelerate downwards at $9.8\frac{m}{s^{2}}$ and hit the ground at approximately the same time.

5 0

4 years ago

A forward horizontal force of 12n is used to pull a crate across a horizontal floor at a constant velocity. If the crate weighs

kow [346]

Explanation:

μ = coefficient of friction.

F = Frictional force = 12N

R = Normal reaction = mg = Weight = 240N

m = mass

g = acceleration due to gravity ≈ 9.8ms—²

μ = F/R

μ = 12/240

μ = ¹/20

μ = 0.05

6 0

2 years ago