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3 years ago

12

If you hold a bar magnet in each hand and bring your hands together, will the force be attractive or repulsive if the magnets ar

e held:
a) with the two north poles together?
b) with a north pole and south pole together

1 answer:

NemiM [27]3 years ago

5 0

Answer:

<u><em>Part A:</em></u>

They will repel each other because same poles repel each other.

<u><em>Part B)</em></u>

They will attract each other because different poles attract each other..

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Consider a blackbody that radiates with an intensity I1I1I_1 at a room temperature of 300K300K. At what intensity I2I2I_2 will t

kap26 [50]

Answer:

Explanation:

We shall apply Stefan's formula

E = AσT⁴

When T = 300

I₁ = Aσ x 300⁴

When T = 400K

I₂ = Aσ x 400⁴

I₂ / I₁ = 400⁴ / 300⁴

= 256 / 81

= 3.16

I₂ = 3.16 I₁ .

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3 years ago

A skater extends her arms, holding a 2 kg mass in each hand. She is rotating about a vertical axis at a given rate. She brings h

Usimov [2.4K]

Explanation:

It is known that relation between torque and angular acceleration is as follows.

$\tau = I \times \alpha$

and, I = $\sum mr^{2}$

So, $I_{1} = 2 kg \times (1 m)^{2} + 2 kg \times (1 m)^{2}$

= 4 $kg m^{2}$

$\tau_{1} = 4 kg m^{2} \times \alpha_{1}$

$\tau_{2} = I_{2} \alpha_{2}$

So, $I_{2} = 2 kg \times (0.5 m)^{2} + 2 kg \times (0.5 m)^{2}$

= 1 $kg m^{2}$

as $\tau_{2} = I_{2} \alpha_{2}$

= $1 kg m^{2} \times \alpha_{2}$

Hence, $\tau_{1} = \tau_{2}$

$4 \alpha_{1} = \alpha_{2}$

$\alpha_{1} = \frac{1}{4} \alpha_{2}$

Thus, we can conclude that the new rotation is $\frac{1}{4}$ times that of the first rotation rate.

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3 years ago

Check all of the following statements that describe velocity.

Nata [24]

Answer:

Choices A, B, and C are correct.

Explanation:

Let us look at each of the choices one by one:

A. It is a vector

Yes. Velocity is a vector, or it's a speed with direction.

B. It is the change in displacement divided by the change in time.

Yes. The velocity can be written as

$v = \dfrac{\Delta\bold{x}}{\Delta t}$

where $\bold{x}$ is the displacement—a vector quantity.

C. It can be measured in meters per second.

Yes. The units of velocity are m/s, but also with a unit vector indicating the direction.

D. It is the slope of the acceleration vs. time graph.

Nope. The velocity is the slope of displacement vs. time graph.

Hence, only choices A, B, and C are correct.

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3 years ago

A plastic rod has been bent into a circle of radius R = 8.00 cm. It has a charge Q1 = +2.70 pC uniformly distributed along one-q

vovikov84 [41]

Answer:

Part a)

$V = -1.52 V$

Part b)

$V = -1.16 V$

Explanation:

Part a)

Electric potential is a scalar quantity

so here we can say that total potential due to a ring on its center is given as

$V = \frac{kQ}{R}$

here we know that

$Q = Q_1 - 6Q_1$

$Q = - 5 Q_1$

$Q_1 = 2.70 pC$

now we have

$V = \frac{(9\times 10^9)(-5\times 2.70 \times 10^{-12})}{0.08}$

$V = -1.52 V$

Part b)

Potential on the axis of the ring is given as

$V = \frac{kQ}{\sqrt{r^2 + R^2}}$

$V = \frac{(9\times 10^9)(-5\times 2.70\times 10^{-12})}{\sqrt{0.08^2 + 0.0671^2}}$

$V = -1.16 V$

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Which of the following will help you stay motivated to achieve your goals?

Dimas [21]

Answer:

C. Post your goals in an obvious place

Explanation:

Being able to look at your goals and check in on the progress of those goals in a place you know where they are so there's no worrying if you might have forgotten one or two and or havent done them is a good way to stay active and keep motivated with your goals. Making notes or specifications on those goals and trying to think over goals is also something you should do. Ignoring or forgetting your goals because you didnt write them down or put them in a secure place can ruin motivation and make you tired cause keeping track of those goals become a chore.

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2 years ago