Sound becomes louder in an empty room. Why? Give reason

With "normal" gravity, we used a potential energy of mgh. Now with the gravity that is more accurate over longer distances we us

Artemon [7]

Answer:

A general solution is $\Delta U=mh\frac{GM}{r^{2}}\frac{r}{r+\Delta h}$ and a particualr case is mgh, it is just to distance around the radius Earth.

Explanation:

We can use a general equation of the potential energy to understand the particular and general case:

The potential energy is defined as $U=-\int F\cdot dx$ , we know that the gravitational force is $F=GmM/r^{2}$ , so we could find the potential energy taking the integral of F.

$U=-GmM/r$ (1)

We can find the particular case, just finding the gravitational potential energy difference:

$\Delta U=U_{f}-U_{i}$ . Here Uf is the potential evaluated in r+Δh and Ui is the potential evaluated in r.

Using (1) we can calculate ΔU.

$\Delta U=-\frac{GmM}{r+\Delta h}+\frac{GmM}{r}$

Simplifying and combining terms we have a simplified expression.

$\Delta U=mh\frac{GM}{r^{2}}\frac{r}{r+\Delta h}$ (2)

Let's call $g=\frac{GM}{r^{2}}$ . It is the acceleration due to gravity on the Earth's surface, if r is the radius of Earth and M is the mass of the Earth and we can write (2) as ΔU=mgh, but if we have distance grader than r we should use (2), otherwise, we could get incorrect values of potential energy.

I hope i hleps you!

3 0

4 years ago

Which device records digital signals? A. V C R tape. B. C D. C. phonograph record. D. audio cassette.

VARVARA [1.3K]

Answer:

CD

Explanation:

5 0

4 years ago

Can someone help me?

stepladder [879]

T=0-15.5/-0.392
=39.5m/s

8 0

4 years ago

Read 2 more answers

Light with a wavelength range of 141–295 nm shines on a silicon surface in a photoelectric effect apparatus, and a reversing pot

Ksju [112]

Answer:

a) the longest wavelength of the light that will eject electrons from the silicon surface is 258.7891 nm

b) maximum kinetic energy will electrons reach the anode is 0.5098 eV

Explanation:

Given:

Wavelength range = 141-295 nm

Potential of 3.5 V

For the silicon, the work function is Φ = 4.8 eV = 7.68x10⁻¹⁹J

Questions:

a) What is the longest wavelength of the light that will eject electrons from the silicon surface, λ = ?

b) With what maximum kinetic energy will electrons reach the anode,

a) The longest wavelength that will eject electrons:

$\lambda =\frac{hc}{\phi }$

Here

h = Planck's constant = 6.625x10⁻³⁴J s

c = speed of light = 3x10⁸m/s

Substituting values:

$\lambda =\frac{6.625x10^{-34}*3x10^{8} }{7.68x10^{-19} } =2.588x10^{-7} m=258.7891nm$

b) The maximum kinetic energy (one electron):

$K=\frac{hc}{\lambda } -\phi =\frac{6.625x10^{-34}*3x10^{8} }{141x10^{-9} } -7.68x10^{-19} =6.416x10^{-19} J=4.0098eV$

Now, you need to calculate the potential difference:

$K'=eV$

Here

e = charge of electron = 1.6x10⁻¹⁹C

Substituting:

$K'=1.6x10^{-19} *3.5=5.6x10^{-19} J=3.5eV$

Now, the maximum kinetic energy of the electrons:

Kmax = 4.0098 - 3.5 = 0.5098 eV

6 0

4 years ago

Find equailent resistance

vovikov84 [41]

Answer:

0.71ohms

Explanation:

AC and CB are in series hence the total resistance is 3+2=5ohms

AD and DB are in series hence the total resistance is 3+2=5ohms

These resistances are parallel to resistance AB

Let the equivalent resistance be R.

For resistances in parallel

Hence the total resistances are:

5//1//5

1/R =1/5 + 1/1 +1/5 = 1+5+1 /5 = 7/5

Hence the total resistance is R= 1/ 7/5 = 1×5/7= 5/7=0.71ohms

4 0

3 years ago