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3 years ago

What is a heat pump? why does it need to put in external work? (2 points) Thank you

Physics

1 answer:

deff fn [24]3 years ago

8 0

<span>Heat pumps use a compressor to make the working fluid condense at a higher:D</span>

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A cloth hat and large rock are dropped at at the same time on the moon

Schach [20]

Answer:

What’s the question??

Explanation:

8 0

3 years ago

A 61.6 turns circular coil with radius 4.44 cm and resistance 2.34 Ω is placed in a magnetic field directed perpendicular to the

Setler [38]

Answer:

Induced emf is 0.324 V

Explanation:

We have,

Number of turns, n = 61.6

Radius of circular coil, r = 4.44 cm

Resistance of coil, R = 2.34 Ω

The magnitude of the magnetic field varies in time according to the expression :

$B=a_1t+a_2t^2$

$a_1=0.0411\\\\a_2=0.044$

The magnitude of the induced emf in the coil is given by :

$\epsilon=\dfrac{d\phi}{dt}\\\\\epsilon=\dfrac{d(NBA)}{dt}\\\\\epsilon=NA\dfrac{dB}{dt}$

$\epsilon=\pi r^2\dfrac{dB}{dt}$

At t = 9.21 s,

$\dfrac{dB}{dt}=(0.0411+2\times 0.044 \times 9.21)\\\\\dfrac{dB}{dt}=0.851\ T/s$

$\epsilon=61.6\times \pi \times (4.44 \times 10^{-2})^2\times 0.851$

$\epsilon=5.27\times 10^{-3}\ V$

So, the magnitude of the induced emf in the coil is 0.324 V

5 0

4 years ago

A solar sail allows a spacecraft to use radiation pressure for propulsion, similar to the way wind propels a sailboat. The sails

Neporo4naja [7]

Answer:

F = 2 I A / c

Explanation:

The radiation pressure on a reflective surface is

P = 2 S / c

Where S is the Poynting Vector and c the speed of light

Furthermore pressure is defined as the ratio of force to area

P = F / A

Let's replace

F / A = 2 S / c

F = 2 S A / c

The poynting vector is the power per unit area that is equal to the intensity

S = I

F = 2 I A / c

7 0

3 years ago

A projectile of mass 9.6 kg is launched from the ground with an initial velocity of 12.4 m/s at angle of 54° above the horizonta

Temka [501]

Answer:

The location is at (3.535, 1.162) m

Solution:

As per the question:

Mass of the projectile, m = 9.6 kg

Initial velocity, v = 12.4 m/s

Angle, $\theta = 54^{\circ}$

Mass of one fragment, m = 6.5 kg

Time taken by the fragment, t = 1.42 s

Height of the fragment, y = 5.9 m

Horizontal distance, x = 13.6 m

Now,

To determine the location of the second fragment:

Horizontal Range, $R = \frac{v^{2}sin2\theta}{g}$

$R = \frac{12.4^{2}sin2(54)}{9.8} = 14.92\ m$

Time of flight, t' = $\frac{2vsin\theta}{g} = \frac{2\times 12.4sin108}{9.8}= 2.406\ s$

Now, for the fragments:

Mass of the other fragment, m' = M - m = 9.6 - 6.5 = 3.1 kg

Distance traveled horizontally:

$s_{x} = vcos\theta = 12.4cos54^{\circ}\times 1.42 = 10.35\ m$

Distance traveled vertically:

$s_{y} = vcos\theta - \frac{1}{2}gt^{2}$

$s_{y} = 12.4sin54^{\circ}\times 1.42 - \frac{1}{2}\times 9.8\times 1.42^{2} = 14.25 - 9.88 = 4.37\ m$

Now,

$s_{x} = \frac{mx + m'x'}{M}$

$10.35= \frac{6.5\times 13.6 + 3.1x'}{9.6}$

x' = 3.535 m

Similarly,

$s_{y} = \frac{my + m'y'}{M}$

$4.37= \frac{6.5\times 5.9 + 3.1y'}{9.6} = 1.162\ m$

The location of the other fragment is at (3.535, 1.162)

5 0

4 years ago

Which of think following materials is the best is the best choice for an insulating material?

RSB [31]

You are correct, the answer is C.

Good insulators are materials that do not allow heat, electricity, light or sound pass through easily. Materials like steel and silver (which are metals) are not good insulators because they make good conductors. They easily allow heat, electricity and the like pass through them.

Thus, the answer is letter C. Rubber.

7 0

3 years ago