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AleksandrR [38]

3 years ago

13

Why does an ice cube melt when you hold it in your hand? Question 1 options: Heat from the ice cube is transferred to your hand.

The ice cube radiates heat to your hand. Your hand transfers temperature to the ice cube. Heat is transferred from your hand to the ice cube.

2 answers:

Sunny_sXe [5.5K]3 years ago

8 0

Your hand transferred temperature to he ice cube

alexira [117]3 years ago

7 0

Your hand transferred temperature to the ice cube

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The decibel level of an orchestra is 90 db, and the violin section achieves a level of 80 dB. How does the sound intensity from

skad [1K]

Answer:

The difference in the decibel corresponses to a constant difference in the loudness perceived.

The refore the sound intensity from the orchestra is like 100 times that of the violin.

Explanation:

4 0

3 years ago

A 4.10 g bullet moving at 837 m/s strikes a 820 g wooden block at rest on a frictionless surface. The bullet emerges, traveling

atroni [7]

Answer:

(a) 1.85 m/s

(b) 4.1 m/s

Explanation:

Data

bullet mass, Mb = 4.10 g

initial bullet velocity, Vbi = 837 m/s

wooden block mass, Mw = 820 g

initial wooden block velocity, Vwi = 0 m/s

final bullet velocity, Vbf = 467 m/s

(a) From the conservation of momentum:

Mb*Vbi + Mw*Vwi = Mb*Vbf + Mw*Vwf

Mb*(Vbi - Vbf)/Mw = Vwf

4.1*(837 - 467)/820 = Vwf

Vwf = 1.85 m/s

(b) The speed of the center of mass speed is calculated as follows:

V = Mb/(Mb + Mw) * Vbi

V = 4.1/(4.1 + 820) * 837

V = 4.1 m/s

6 0

3 years ago

The diagram shows movement of thermal energy. At bottom a fire has red curved lines labeled Y with arrowheads pointing upward to

Pepsi [2]

Answer:

X and Z

Explanation:

Conduction occurs through direct physical contact. Heat transferred from the pot to the handle, and from the handle to the hand, are both examples of conduction.

6 0

3 years ago

Read 2 more answers

The intensity of light from a star (its brightness) is the power it outputs divided by the surface area over which it’s spread:

kow [346]

Answer:

$\frac{d_{1}}{d_{2}}=0.36$

Explanation:

1. We can find the temperature of each star using the Wien's Law. This law is given by:

$\lambda_{max}=\frac{b}{T}=\frac{2.9x10^{-3}[mK]}{T[K]}$ (1)

So, the temperature of the first and the second star will be:

$T_{1}=3866.7 K$

$T_{2}=6444.4 K$

Now the relation between the absolute luminosity and apparent brightness is given:

$L=l\cdot 4\pi r^{2}$ (2)

Where:

L is the absolute luminosity
l is the apparent brightness
r is the distance from us in light years

Now, we know that two stars have the same apparent brightness, in other words l₁ = l₂

If we use the equation (2) we have:

$\frac{L_{1}}{4\pi r_{1}^2}=\frac{L_{2}}{4\pi r_{2}^2}$

So the relative distance between both stars will be:

$\left(\frac{d_{1}}{d_{2}}\right)^{2}=\frac{L_{1}}{L_{2}}$ (3)

The Boltzmann Law says, $L=A\sigma T^{4}$ (4)

σ is the Boltzmann constant
A is the area
T is the temperature
L is the absolute luminosity

Let's put (4) in (3) for each star.

$\left(\frac{d_{1}}{d_{2}}\right)^{2}=\frac{A_{1}\sigma T_{1}^{4}}{A_{2}\sigma T_{2}^{4}}$

As we know both stars have the same size we can canceled out the areas.

$\left(\frac{d_{1}}{d_{2}}\right)^{2}=\frac{T_{1}^{4}}{T_{2}^{4}}$

$\frac{d_{1}}{d_{2}}=\sqrt{\frac{T_{1}^{4}}{T_{2}^{4}}}$

$\frac{d_{1}}{d_{2}}=\sqrt{\frac{T_{1}^{4}}{T_{2}^{4}}}$

$\frac{d_{1}}{d_{2}}=0.36$

I hope it helps!

5 0

3 years ago

A galaxy spectrum has a redshift of 70,000 km per second. If the Hubble constant is 70 km per second per Mpc (megaparsec), how f

gogolik [260]

Using the Hubble law v = H₀d where v = recessional speed = 70,000 km per second H₀ = hubble constant = 70 km/s/Mpc and d = distance of galaxy.

Making d subject of the formula, we have

d = v/H₀

Substituting the values of the variables into the equation, we have

d = v/H₀

d = 70000 km/s/70 km/s/Mpc

d = 1000 Mpc

So, the galaxy is 1000 Mpc away from us.

Learn more about hubble law here:

brainly.com/question/18484687

8 0

3 years ago