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Pie
3 years ago
10

You want to use a metal bar as a resistor. Its dimensions are 1 by 3 by 13 units. To get the largest resistance from the bar, yo

u should attach leads to the two opposite sides that have dimensions of 1 by 3 units. All configurations give the same resistance. 3 by 13 units. 1 by 13 units. None of the above.
Physics
1 answer:
Leno4ka [110]3 years ago
7 0

Answer:

1 by 3 units

Explanation:

The resistance (R) of a conductor is given by the formula:

R = ρL / A

where L is the length of the conductor, ρ is resistivity and A is the cross sectional area.

Let us assume that the metal bar has a resistivity of ρ.

a) If the leads is attached to the two opposite sides that have dimensions of 1 by 3 units.

The length of the bar would be 13 units and the cross sectional area (A) would be = 1 * 3 = 3 units²

R₁ = ρL / A =  ρ(13) / 3 = 13ρ / 3

b) If the leads is attached to the two opposite sides that have dimensions of 3 by 13 units.

The length of the bar would be 1 units and the cross sectional area (A) would be = 3 * 13 = 39 units²

R₂ = ρL / A  = ρ(1) / 39 = ρ / 39

c) If the leads is attached to the two opposite sides that have dimensions of 1 by 13 units.

The length of the bar would be 3 units and the cross sectional area (A) would be = 1 * 13 = 13 units²

R₃ = ρL / A = ρ(3) / 13 = 3ρ / 13

Therefore we can see that the largest resistance is gotten If the leads is attached to the two opposite sides that have dimensions of 1 by 3 units

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All organisms in Kingdom Animalia are multicellular, meaning their bodies are composed of more than one cell. Which other charac
k0ka [10]
Well,

For the first one, the answer would be C, because all organisms in Kingdom Animalia must eat in order to survive.

For the second one, all of the options are in Kingdom Animalia, but worms (A) and clams (C) are invertebrates.  So that leaves options B and D.
4 0
3 years ago
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An oscillator consists of a block attached to a spring (k = 427 N/m). At some time t, the position (measured from the system's e
White raven [17]

Answer:

a) 4.49Hz

b) 0.536kg

c) 2.57s

Explanation:

This problem can be solved by using the equation for he position and velocity of an object in a mass-string system:

x=Acos(\omega t)\\\\v=-\omega Asin(\omega t)\\\\a=-\omega^2Acos(\omega t)

for some time t you have:

x=0.134m

v=-12.1m/s

a=-107m/s^2

If you divide the first equation and the third equation, you can calculate w:

\frac{x}{a}=\frac{Acos(\omega t)}{-\omega^2 Acos(\omega t)}\\\\\omega=\sqrt{-\frac{a}{x}}=\sqrt{-\frac{-107m/s^2}{0.134m}}=28.25\frac{rad}{s}

with this value you can compute the frequency:

a)

f=\frac{\omega}{2\pi}=\frac{28.25rad/s}{2\pi}=4.49Hz

b)

the mass of the block is given by the formula:

f=\frac{1}{2\pi}\sqrt{\frac{k}{m}}\\\\m=\frac{k}{4\pi^2f^2}=\frac{427N/m}{(4\pi^2)(4.49Hz)^2}=0.536kg

c) to find the amplitude of the motion you need to know the time t. This can computed by dividing the equation for v with the equation for x and taking the arctan:

\frac{v}{x}=-\omega tan(\omega t)\\\\t=\frac{1}{\omega}arctan(-\frac{v}{x\omega })=\frac{1}{28.25rad/s}arctan(-\frac{-12.1m/s}{(0.134m)(28.25rad/s)})=2.57s

Finally, the amplitude is:

x=Acos(\omega t)\\\\A=\frac{0.134m}{cos(28.25rad/s*2.57s )}=0.45m

5 0
2 years ago
A van starts off 152 miles directly north from the city of Springfield. It travels due east at a speed of 25 miles per hour. Aft
erastovalidia [21]

Answer:

12.84 miles per hour

Explanation:

Given:

Vertical distance of starting point of van from Springfield (d) = 152 miles

Speed in east direction (s) = 25 mph

Distance traveled in east direction (e) = 91 miles

Let the direct distance from Springfield of the van be 'x' at any time 't'.

Now, from the question, it is clear that, the vertical distance of van is fixed at 152 miles and only the horizontal distance is changing with time.

Now, consider a right angled triangle SNE representing the given situation.

Point S represents Springfield, N represents the starting point of van and E represents the position of van at any time 't'.

SN = d = 152 miles (fixed)

Now, using the pythagorean theorem, we have:

SE^2=SN^2+NE^2\\\\x^2=d^2+e^2\\\\x^2=(152)^2+e^2----(1)

Now, differentiating both sides with respect to time 't', we get:

2x\frac{dx}{dt}=0+2e\frac{de}{dt}\\\\\frac{dx}{dt}=\frac{e}{x}\frac{de}{dt}

Now, we are given speed as 25 mph. So, \frac{de}{dt}=25\ mph

Also, when e=91\ mi, we can find 'x' using equation (1). This gives,

x^2=23104+(91)^2\\\\x=\sqrt{31385}=177.16\ mi

Now, plug in the values of 'e' and 'x' and solve for \frac{dx}{dt}. This gives,

\frac{dx}{dt}=\frac{91}{177.16}\times 25\\\\\frac{dx}{dt}=12.84\ mph

Therefore, the distance between the van and Springfield is changing at a rate of 12.84 miles per hour

6 0
3 years ago
Which method of measurement would be accurate but lack precision?
kodGreya [7K]

Answer:

B

Explanation:

reading the volume of water in a graduated cylinder which can be read to the nearest mL is accurate, it lacks precision due to the bottom meniscus formed.

the bottom meniscus may cause a wrong reading due to refraction of light

7 0
2 years ago
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Explanation:

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<em><u>HAPPY TO HELP</u></em>

8 0
2 years ago
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