How does the intensity of a sound wave change if the distance from the

anyanavicka [17]

The answer should be c....

6 0

4 years ago

A sphere is originally at a temperature of 500°c. The sphere is melted and recast, without loss of mass, into a cube with the sa

aleksandr82 [10.1K]

Answer: The value of the celsius temperature of the cube is 472.2°c.

Explanation:

The expression for the power radiated is as follows;

$P=A\epsilon\sigma T^{4}$

Here, A is the area, $\sigma$ is the stefan's constant, $\epsilon$ is the emissivity and T is the temperature.

It is given in the problem that A sphere is originally at a temperature of 500°c. The sphere is melted and recast, without loss of mass, into a cube with the same emissivity as the sphere.

Then the expression for the radiated power for the cube and the sphere can be expressed as;

$A_{1}\epsilon \e\sigma T_{1}^{4}=A_{2}\epsilon \e\sigma T_{2}^{4}$

Here, $A_{1}$ is the area of the sphere, $A_{2}$ is the area of the cube, $T_{1}$ is the temperature of the sphere and $T_{2}$ is the temperature of the cube.

The radiated powers and emissivity of the cube and the sphere are same.

$A_{1}T_{1}^{4}=A_{2}T_{2}^{4}$

The area of the sphere is $A_{1}=4\pi \times r^{2}$ .

Here, r is the radius of the sphere.

The area of the cube is $A_{2}=6\times a^{2}$ .

Here, a is the edge of the cube.

Put $A_{1}=4\pi \times r^{2}$ and $A_{2}=6\times a^{2}$ .

$T_{2}=T_{1}(\frac{2\pi }{3}\times (\frac{r}{a})^{2})^{\frac{1}{4}}$ ....(1)

The masses and the densities of the sphere and the cube are same. Then the volumes are also same.

$V_{1}=V_{2}$

Here, $V_{1},V_{1}$ are the volumes of the sphere and the cube.

$\frac{4}{3}\pi r^{3}=a^{3}$

$\frac{r}{a}=(\frac{3}{4\pi })^{\frac{1}{3}}$

Put this value in the equation (1).

$T_{2}=T_{1}(\frac{2\pi }{3}\times (\frac{r}{a})^{2})^{\frac{1}{4}}$ $T_{2}=T_{1}(\frac{2\pi }{3}\times ((\frac{3}{4\pi })^{\frac{1}{3}})^{2})^{\frac{1}{4}}$

Put T_{1}=500°c.

$T_{2}=(500)(\frac{2\pi }{3}\times (\frac{3}{4\pi })^{\frac{2}{3}})^{\frac{1}{4}}$

$T_{2}=472.2^{\circ}c$

Therefore, the value of the celsius temperature of the cube is 472.7°c.

5 0

3 years ago

A 750 kg car is moving at 20.0 m/s at a height of 5.0 m above the bottom of a hill when it runs out of gas. From there, the car

S_A_V [24]

Answer:

Explanation:

Kinetic energy at the height = 1/2 m v²

= 1/2 x 750 x 20²

= 150000 J

Its potential energy = mgh

= 750 x 9.8 x 5

=36750 J

Total energy = 186750 J

Its total kinetic energy will be equal to 186750 J , according to conservation of mechanical energy

If v be its velocity at the bottom

1/2 m v² = 186750

v = √498

= 22.31 m /s

5 0

3 years ago

If you want to check on what conditions were like in the universe a few hundred thousand years after the Big Bang, what sort of

Klio2033 [76]

Big Bang, what sort of instrument would it be best to use: gravity.

The force of attraction between any two objects in the universe is known as gravity or gravitational force.

The mass of the object and the square of the distance between them determine the force of attraction. The weakest known force in nature, it is by far. There are only two factors that matter when discussing the gravitational force between two objects: mass and distance.

The square of the distance between two things has an inverse relationship with the force of gravity, which depends directly on the masses of the two items. The best theories of string theory propose that gravity is so weak because, in contrast to other forces, it may enter and exit these extra dimensions. We only get to taste a tiny bit of gravity's tremendous power.

Learn more about gravity herebrainly.com/question/10470988

#SPJ4.

6 0

2 years ago

Stairway must have uniform riser height and tread depth; variations in riser height or tread depth shall not be over _______ inc

alexandr1967 [171]

Answer:

$\frac{3}{8} inches$

Explanation:

the variations in riser height or tread depth should not be grater than $\frac{3}{8} inches$ that is equal to 9.5 mm but the maximum riser height should be the $\frac{81}{4} inch$ but variation in riser height should not exceed to $\frac{3}{8} inches$ . The minimum riser height should be 7 inches which is equal to the 178 mm

5 0

4 years ago