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3 years ago

Explain why a crack in glass looks brighter than the rest of the glass

Physics

1 answer:

m_a_m_a [10]3 years ago

8 0

Answer:

Because nothing is blocking the LIGHT!

Explanation:

Light may still be shining on the whole glass but if it wasn't there light would shine brighter than if it was there.

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docker41 [41]

Answer:

what do the choices look like

Explanation:

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3 years ago

f you were trying to build a soundproof room, which of the following materials would you choose in order to absorb the most soun

musickatia [10]

If you don't have the coefficient of absorption, I would say Heavy curtains.

Hope this helps :)

5 0

3 years ago

A fisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surfac

Lemur [1.5K]

Answer:

a) v = 0.9167 m / s, b) A = 0.350 m, c) v = 0.9167 m / s, d) A = 0.250 m

Explanation:

a) to find the velocity of the wave let us use the relation

v = λ f

the wavelength is the length that is needed for a complete wave, in this case x = 5.50 m corresponds to a wavelength

λ = x

the period is the time for the wave to repeat itself, in this case t = 3.00 s corresponds to half a period

T / 2 = t

T = 2t

period and frequency are related

f = 1 / T

f = 1 / 2t

we substitute

v = x / 2t

v = 5.50 / 2 3

v = 0.9167 m / s

b) the amplitude is the distance from a maximum to zero

2A = y

A = y / 2

A = 0.700 / 2

A = 0.350 m

c) The horizontal speed of the traveling wave (waves) is independent of the vertical oscillation of the particles, therefore the speed is the same

v = 0.9167 m / s

d) the amplitude is

A = 0.500 / 2

A = 0.250 m

4 0

3 years ago

The length of a simple pendulum is 0.81 mand the mass of the particle (the "bob") at the end of the cable is0.23 kg. The pendulu

Gemiola [76]

Answer:

$\displaystyle w=3.478\ rad/sec$

$M=0.0182\ J$

$v=0.398\ m/s$

Explanation:

<u>Simple Pendulum</u>

It's a simple device constructed with a mass (bob) tied to the end of an inextensible rope of length L and let swing back and forth at small angles. The movement is referred to as Simple Harmonic Motion (SHM).

(a) The angular frequency of the motion is computed as

$\displaystyle w=\sqrt{\frac{g}{L}}$

We have the length of the pendulum is L=0.81 meters, then we have

$\displaystyle w=\sqrt{\frac{9.8}{0.81}}$

$\displaystyle w=3.478\ rad/sec$

(b) The total mechanical energy is computed as the sum of the kinetic energy K and the potential energy U. At its highest point, the kinetic energy is zero, so the mechanical energy is pure potential energy, which is computed as

$U=mgh$

where h is measured to the reference level (the lowest point). Please check the figure below, to see the desired height is denoted as Y. We know that

$H+Y=L$

And

$H=L\ cos\alpha$

Solving for Y

$Y=L(1-cos\alpha )$

$Since\ \alpha=8.1^o, L=0.81\ m$

$Y=0.0081\ m$

The potential energy is

$U=mgh=0.23\ kg(9.8\ m/s^2)(0.0081\ m)$

$U=0.0182\ J$

The mechanical energy is, then

$M=K+U=0+U=U$

$M=0.0182\ J$

(c) The maximum speed is achieved when it passes through the lowest point (the reference for h=0), so the mechanical energy becomes all kinetic energy (K). We know

$\displaystyle K=\frac{mv^2}{2}$