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3 years ago

9

What minimum number of 45 W lightbulbs must be connected in parallel to a single 240 V household circuit to trip a 50.0 A circui

t breaker? ____lightbulbs

1 answer:

Black_prince [1.1K]3 years ago

5 0

Answer:267

Explanation:

Given

Power of light bulbs is 45 W

and voltage applied is 240 V

Allowable current is 50 A

and $P=\frac{V^2}{R}$

$R=\frac{V^2}{P}$

$R=\frac{240\times 240}{45}=1280 \Omega$

and wire will trip if resistance drop below

$R_{total}=\frac{240}{50}=4.8 \Omega$

Therefore $R_{total}=\frac{R}{n}$

$n=\frac{R}{R_{total}}=\frac{1280}{4.8}=266.667 \approx 267$

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Answer:

Yes

Explanation:

If the acceleration has an opposite direction to the velocity of the car, this means that it is opposed to is motion. Therefore, it is called deceleration, since the car's velocity will decrease until it stops and then will start it moving towards the west.

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3 years ago

What is the difference between the number of electrons in an atom of selenium, Se, and the number of electrons in an atom of alu

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3 years ago

Read 2 more answers

2. A student places an object with a mass of m on a disk at a position r from the center of the disk. The student starts rotatin

ycow [4]

Answer:

$\frac{0.065}{r}$

Explanation:

The maximum velocity of an object moving in a curve beyond which it will slide off the curve is given by the relationship in equation (1);

$v=\sqrt{\mu gr}....................(1)$

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Given;

v = 0.8m/s

g = $9.81m/s^2$

r = ?

$\mu=?$

In order to solve for $\mu$ , we can simply make it the subject of formula from equation (1) as follows;

$v^2=\mu gr\\hence\\\mu=\frac{v^2}{gr}.................(2)$

since we were not given the value of r, we can just substitute other known values, then solve and leave the answer in terms of r.

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3 years ago

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Answer:

The correct answer is Dean has a period greater than San

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T² = (4π² / G M) r³

When applying this equation to our case, the planet with a greater orbit must have a greater period.

Consequently Dean must have a period greater than San which has the smallest orbit

The correct answer is Dean has a period greater than San

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2 years ago

An object at 27°C has its temperature increased to 37°C.

Firlakuza [10]

Answer:

b. 14

Explanation:

$T_{i}$ = Initial temperature = 27 °C = 27 + 273 = 300 K

$T_{f}$ = Final temperature = 37 °C = 37 + 273 = 310 K

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$P_{f}$ = Final Power radiated by the object

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Percentage increase in power is given as

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3 years ago