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3 years ago

The diagram below shows rock is affected when water enters cracks in rock,freezes and becomes ice

Physics

1 answer:

dusya [7]3 years ago

8 0

Water expands when it freezes so it will make the crack even bigger and eventually cause it to completely break.

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Calculate the force of gravity on a 1–kilogram box located at a point 1.3 × 10^7 meters from the center of Earth. (The value of

Kryger [21]

Answer:

A. 2.36

Explanation:

This is the right answer for Plato users!

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3 years ago

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A disk, with a radius of 0.25 m, is to be rotated like a merry-go-round through 800 rad, starting from rest, gaining angular spe

torisob [31]

Answer:

a) $T_{min} = 80\,s$

Explanation:

a) Let consider that disk accelerates and decelerates at constant rate. The expression for angular acceleration and deceleration are, respectively:

Acceleration

$\alpha_{1} = \frac{\omega_{max}^{2}}{2\cdot (400\,rad)}$

Deceleration

$\alpha_{2} = -\frac{\omega_{max}^{2}}{2\cdot (400\,rad)}$

Since angular acceleration and deceleration have same magnitude but opposite sign. Let is find the maximum allowed angular speed from maximum allowed centripetal acceleration:

$a_{r,max} = \omega_{max}^{2}\cdot r$

$\omega_{max} = \sqrt{\frac{a_{r,max}}{r} }$

$\omega_{max} = \sqrt{\frac{100\,\frac{m}{s^{2}} }{0.25\,m} }$

$\omega_{max} = 20\,\frac{rad}{s}$

Maximum magnitude of acceleration/deceleration is:

$\alpha = 0.5\,\frac{rad}{s^{2}}$

The least time require for rotation is:

$T_{min} = 2\cdot \left(\frac{20\,\frac{rad}{s} }{0.5\,\frac{rad}{s^{2}} } \right)$

$T_{min} = 80\,s$

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3 years ago

You’re an electrical engineer designing an alternator (the generator that charges a car’s battery). Mechanical engineers specify

makvit [3.9K]

Answer:

I will specify a value of 0.009T for the alternator’s magnetic field

Explanation:

E_peak = 14 V

d = 10cm = 0.1m, so r = 0.1/2 =0.05m

N = 250 turns

f = 1200rpm = (1200rp/m x 1m/60sec) = 20 revolutions per second

At peak performance, peak voltage is given by the equation;

E_peak = NABω

Let's make the magnetic field B the subject;

B = E_peak/(NAω)

Now we know that ω = 2πf

Thus, ω = 2π x 20 revs/s = 125.664 revs/s.

Let's convert it to the standard unit which is rad/s.

1 rev/s = 6.283 rad/s

Thus, 125.664 revs/s = 125.664 x 6.283 = 789.55 rad/s

Area (A) = πr² = π x 0.05² = 0.007854 m²

Thus, plugging in the relevant values to get;

B = 14/[(250 x 0.007854 x 789.55)] = 0.009T

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3 years ago

True or False. If you kick a soccer ball and there are no forces like friction acting on it will it keep moving?

VLD [36.1K]

Answer:

Yes

Explanation:

Newton's laws states that gravity or force will stop the balls movement. Think of space for a example, if you pushed a soccer ball into space if would float for eternity.

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3 years ago

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Drag the boxes to other mechanical, both or electromagnetic. some may be for both some may be for electromagnetic and some may b

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Answer:

infared light is both

can be reflected is electromagnetic

longitude wave is mechanical

visible light is electromagnetic

transfers energy is both

transfers waves is mechanical

requires midium i think is both

speed dependent is both

Explanation:

hope this helps

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3 years ago