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2 years ago

Which of the following is true about magnetic poles?

2 answers:

5 0

The answer is A. Have you ever heard the saying, opposites attract? That comes from magnetism. Like poles repel each other while opposites attract.

Alex Ar [27]2 years ago

5 0

A. because the like pole of the inner magnet would be attracted to orienting towards the like pole, The solenoid opposites attract. the main difference between a bar magnet and a solenoid is that there isn't the hollow interior of a bar magnet where "like poles attract". i stand corrected.<span> </span>

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A robot is exploring charon, the dwarf planet pluto's largest moon. Gravity on charon is 0.278 meters per second [m divided b

DochEvi [55]

In order to find the efficiency first we will find the Change in Potential energy of the small stone that robot picked up

First we will find the mass of the stone

As it is given that stone is spherical in shape so first we will find its volume

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

$V = \frac{4}{3}\pi *(\frac{0.06}{2})^3$

$V = 1.13 * 10^{-4} m^3$

Now it is given that it's specific gravity is 10.8

So density of rock is

$\rho = 10.8 * 10^3 kg/m^3$

mass of the stone will be

$m = \rho V$

$m = 10.8* 10^3 * 1.13 * 10^{-4}$

$m = 1.22 kg$

now change in potential energy is given as

$\Delta U = mgH$

here

g = gravity on planet = 0.278 m/s^2

H = height lifted upwards = 15 cm

$\Delta U = 1.22* 0.278 * 0.15$

$\Delta U = 0.051 J$

Now energy supplied by internal circuit of robot is given by

$E = Vit$

V = voltage supplied = 10 V

i = current = 1.83 mA

t = time = 12 s

$E = 10* 1.83 * 10^{-3} * 12$

$E = 0.22 J$

Now efficiency is defined as the ratio of output work with given amount of energy used

$\eta = \frac{\Delta U}{E}*100$

$\eta = \frac{0.051}{0.22} = 0.23$

so efficiency will be 23 %

5 0

2 years ago

Most of the elements (85%) in the periodic table are.

Rasek [7]

Most of the elements are metals

4 0

2 years ago

Read 2 more answers

Which of the following is the best example of a primary circular reaction?

olga55 [171]

Primary Circular Reactions (1-4 months): This substage involves coordinating sensation and new schemas. For example, a child may suck his or her thumb by accident and then later intentionally repeat the action. These actions are repeated because the infant finds them pleasurable.

4 0

2 years ago

What can always be said about a negatively-charged ion?

KiRa [710]

Answer: A negatively-charged ion always has more electrons than protons

Explanation:

First, we know that the elementary negative charge is the electron, while the positive one is the proton. Such that both have the same charge in magnitude, but a different sign. Such that if we have the same number of electrons and protons in an atom, the charge of this atom will be neutral.

And an ion is an atom with a different number of electrons and protons, so the charge of the atom is not neutral.

Then if we have a negatively-charged ion, the charge of this atom is negative. Then we must have a larger number of electrons (the negative ones) than protons (the positive ones)

Then the correct option is:

A negatively-charged ion always has more electrons than protons

5 0

2 years ago

Ethan made a diagram to compare examples of the first and second laws of thermodynamics. What belongs in the areas marked X and

bazaltina [42]

Answer:

The answer is X: Thermal energy is converted to light energy

Y: A cold spoon placed in hot liquid gets warmer

Explanation:

I took the quiz

4 0

3 years ago