1. Find the charge if the number of electrons is 4 x 10-18

Find the intensity of a 55 dB sound given lo-10-12 wm2

Inessa05 [86]

Answer:

Intensity= $I=3.16\times 10^{-7}\ W\ m^{-2}$

Explanation:

Given:

$\beta=55\ dB\\I_o=10^{-12}\ W\ m^{-2}$

The sound level $\beta$ in dB with intensity $I$

and reference intensity $I_0$ is given by:

$\beta(dB)=10 \log_{10}(\frac{I}{I_0})$

Plugging in values.

$55=10 \log_{10}(\frac{I}{10^{-12}})$

Dividing both sides by 10.

$\frac{55}{10}=\frac{10 \log_{10}(\frac{I}{10^{-12}})}{10}$

$5.5=\log_{10}\frac{I}{10^{-12}}$

The above can be written as

$10^{5.5}=\frac{I}{10^{-12}}$

Multiplying both sides by $10^{-12}$

$10^{5.5}\times 10^{-12}=10^{-12}\times \frac{I}{10^{-12}}$

$10^{(5.5-12)}=I$

$10^{(-7.5)}=I$

∴ $I=3.16\times 10^{-7}\ W\ m^{-2}$

Intensity = $I=3.16\times 10^{-7}\ W\ m^{-2}$

7 0

3 years ago

A student makes a simple pendulum by attaching a mass to the free end of a 1.50-meter length of string suspended from the ceilin

Fofino [41]

Answer:

The mass has likely lost some of its mechanical energy to resistance on its path.

Explanation:

The mechanical energy of an object is the sum of its kinetic and potential energies (KE and PE.) Ideally, the mechanical energy of a simply pendulum should be "conserved." In other words, the sum of the kinetic and potential energy of the simply pendulum should stays the same as it travels along its path.

Indeed, as the pendulum travels, some of its PE will convert to KE and back. However, the sum of these two energies is supposed to stay the same.

When the pendulum moves from the highest point to the bottom of the path, some of its PE converts to KE. (The pendulum speeds up in this process.)
When the pendulum moves from the bottom of its path to the opposite side, its KE is converted back to PE. (The pendulum slows down as it moves towards the other side of the path.)

However, in practice, the mechanical energy of pendulums isn't always conserved. For example, various kinds of resistances (such as air resistance) act on the pendulum as it moves. That would slow down the pendulum. Some of the pendulum's energies would be converted to heat and is lost to the surroundings.

In effect, the mechanical energy of the pendulum would become smaller and smaller over time. When the pendulum travels back towards the girl, its potential energy would be smaller than the initial value when at the girl's chin.

5 0

3 years ago

Calculate the period (T) of uniform circular motion if the velocity is 40.0 m/s and centripetal acceleration is 20.0 m/s2.

kirill [66]

T is the time for a whole round.

centripetal acceleration = V^2/R,

20 = 40^2 / R, find R = 40^2/20 = 40*40/20 = 80 m, right?

Now, one round is L = 2*pi*R = 2*pi*80 = 160*pi

And T = L/v (distance/speed) = 160*pi/40 = 4*pi seconds, or ~ 12.57 s

3 0

3 years ago

Differentiate between angular displacement and linear displacement.

Sauron [17]

Answer:

The angular displacement is not a length (not measured in meters or feet), so an angular displacement is different than a linear displacement. ... As the object rotates through the angular displacement phi, the point on the edge of the disk moves distance sa along a circular path.

7 0

2 years ago

The illustration shows a rollercoaster and indicates four different positions the car might be at as it moves along the track. A

Vanyuwa [196]

Answer:

Point a

Explanation:

The potential energy of an object is given by :

P = mgh

m is mass, g is acceleration due to gravity, h is height above ground level.

Potential energy is directly proportional to the position of an object.

In the attached figure, the maximum height is shown at point (a). It means it will have maximum potential energy at a as compared to b,c and d.

5 0

3 years ago

1. Find the charge if the number of electrons is 4 x 10-18​

1. Find the charge if the number of electrons is 4 x 10-18