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2 years ago

Write an equation that expresses the first law of thermodynamics in terms of heat and work.

Physics

1 answer:

OleMash [197]2 years ago

3 0

Answer:

Heat Input = Work Output (at 100% efficiency)

ΔQ = ΔW

(you cannot get something for nothing)

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Determine the stiffness of the spring to hold the 85-kg crate in the position shown.

GalinKa [24]

Correct position spring hold it

5 0

3 years ago

The first artificial satellite to orbit the Earth was Sputnik I, launched October 4, 1957. The mass of Sputnik I was 83.5 kg, an

9966 [12]

Answer:

$-4.941*10^8J.$

Explanation:

To solve this exercise it is necessary to take into account the concepts related to gravitational potential energy, as well as the concept of perigee and apogee of a celestial body.

By conservation of energy we know that,

$\Delta U = \Delta_{perogee}-\Delta_{Apogee}$

Where,

$U= \frac{-GmM_e}{r}$

Replacing

$\Delta U = \frac{-GmM_e}{r_p}- \frac{-GmM_e}{r_a}$

$\Delta U = GmM_e (\frac{1}{r_A}-\frac{1}{r_p})$

Our values are given by,

$m = 85.5Kg$

$M_e = 5.97*10^{24}Kg$

$r_A = 7330Km$

$r_p = 6610Km$

$G = 6.67*10^{-11}Nm^2/Kg^2$

Replacing at the equation,

$\Delta U = (6.67*10^{-11})(85.5)(5.97*10^{24}) (\frac{1}{7330}-\frac{1}{6610})$

$\Delta U = -4.941*10^8J$

Therefore the Energy necessary for Sputnik I as it moved from apogee to perigee was $-4.941*10^8J.$

4 0

3 years ago

Which best compares AC and DC?

Naily [24]

Yea im pretty sure its B

5 0

3 years ago

Read 2 more answers

Singly charged uranium-238 ions are accelerated through a potential difference of 2.20 kV and enter a uniform magnetic field of

Aleonysh [2.5K]

Answer:

r = 0.0548 m

Explanation:

Given that,

Singly charged uranium-238 ions are accelerated through a potential difference of 2.20 kV and enter a uniform magnetic field of 1.90 T directed perpendicular to their velocities.

We need to find the radius of their circular path. The formula for the radius of path is given by :

$r=\dfrac{1}{B}\sqrt{\dfrac{2mV}{q}}$

m is mass of Singly charged uranium-238 ion, $m=3.95\times 10^{-25}\ kg$

q is charge

So,

$r=\dfrac{1}{1.9}\times \sqrt{\dfrac{2\times 3.95\times 10^{-25}\times 2.2\times 10^3}{1.6\times 10^{-19}}}\\\\r=0.0548\ m$

So, the radius of their circular path is equal to 0.0548 m.

4 0

3 years ago

Why is an electromagnet used instead of a permanent magnet in magnetic cranes?

natali 33 [55]

Answer:

an electromagnet is a metal which has the ability to turn into a magnet on passing electricity through it .

But once the electric flow is withdrawn the circuit breaks and it no more behaves like a magnet.

but this is not so in permanent magnets

Explanation:

thus electromagnet is used in magnetic cranes bcoz their magnetism can be controlled conveniently.

8 0

3 years ago

Read 2 more answers