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3 years ago

12

Which statement best describes the type of magnetism generated by attaching a wire to a battery and wrapping the wire around an

iron nail?

1 answer:

Mazyrski [523]3 years ago

4 0

It only occurs when there is an electric current

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The circumference of a sphere was measured to be

professor190 [17]

To solve this problem we will apply the concepts related to the calculation of the surface, volume and error through the differentiation of the formulas given for the calculation of these values in a circle. Our values given at the beginning are

$\phi = 76cm$

$Error (dr) = 0.5cm$

The radius then would be

$\phi = 2\pi r \\76cm = 2\pi r\\r = \frac{38}{\pi} cm$

And

$\frac{d\phi}{dr} = 2\pi \\d\phi = 2\pi dr \\0.5 = 2\pi dr$

PART A ) For the Surface Area we have that,

$A = 4\pi r^2 \\A = 4\pi (\frac{38}{\pi})^2\\A = \frac{5776}{\pi}$

Deriving we have that the change in the Area is equivalent to the maximum error, therefore

$\frac{dA}{dr} = 4\pi (2r) \\dA = 4r (2\pi dr)$

Maximum error:

$dA = 4(\frac{38}{\pi})(0.5)$

$dA = \frac{76}{\pi}cm^2$

The relative error is that between the value of the Area and the maximum error, therefore:

$\frac{dA}{A} = \frac{\frac{76}{\pi}}{\frac{5776}{\pi}}$

$\frac{dA}{A} = 0.01315 = 1.31\%$

PART B) For the volume we repeat the same process but now with the formula for the calculation of the volume in a sphere, so

$V = \frac{4}{3} \pi r^3$

$V = \frac{4}{3} \pi (\frac{38}{\pi})^3$

$V = \frac{219488}{3\pi^2}$

Therefore the Maximum Error would be,

$\frac{dV}{dr} = \frac{4}{3} 3\pi r^2$

$dV = 2r^2 (2\pi dr)$

$dV = 4r^2 (\pi dr)$

Replacing the value for the radius

$dV = 4(\frac{38}{\pi})^2(0.5)$

$dV = \frac{2888}{\pi^2} cm^3$

And the relative Error

$\frac{dV}{V} = \frac{ \frac{2888}{\pi^2}}{ \frac{219488}{3\pi^2} }$

$\frac{dV}{V} = 0.03947$

$\frac{dV}{V} = 3.947\%$

3 0

3 years ago

Sometimes referred to as the law of inertia. An object at rest stays at rest and an object in motionstays in motion with the sam

Lera25 [3.4K]

Answer:

D

Explanation:

Newtons first law states that if an object is at rest it will stay at rest only if an unbalanced force acts on it. As well as if an object is in motion it will stay in motion unless an unbalanced force acts on it.

Ps- The object will stay moving in the same speed and direction.

5 0

3 years ago

How long would it take for a car to travel 200 km if it has an average speed of 55 km hr?

Rainbow [258]

Answer:

3.63 hours or 3 and 37.5 minutes

Explanation:

200/55

Hope this helps :)

6 0

3 years ago

If a vibrating string is made shorter (i.e., by holding your finger on it), what effect does

Ghella [55]

<span>Pitch and frequency are more or less the same thing - high pitch = high frequency.
The freqency of vibration of a string f = 1/length (L) so as length decreases the frequency increases.</span>

4 0

3 years ago

Explain: What happens to the velocity of a stream as the size of the sediment increases?

artcher [175]

Answer:

Also, as stream depth increases, the hydraulic radius increases thereby making the stream more free flowing. Both of these factors lead to an increase in stream velocity. The increased velocity and the increased cross-sectional area mean that discharge increases.

8 0

3 years ago