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3 years ago

Noah drops a rock with a density of 1.73 g/cm3 into a pond. Will the rock float or sink? Explain your answer.

Physics

1 answer:

wel3 years ago

5 0

Answer:

Sink

Explanation:

The normal density of water is 1 g/cm3. Since the rock has a higher density of 1.72g/cm3, it will sink in water.

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You are trying to overhear a juicy conversation, but from your distance of 20.0 m , it sounds like only an average whisper of 30

12345 [234]

Answer:

r₂ = 0.2 m

Explanation:

given,

distance = 20 m

sound of average whisper = 30 dB

distance moved closer = ?

new frequency = 80 dB

using formula

$\beta = 10 log(\dfrac{I_1}{I_0})$

I₀ = 10⁻¹² W/m²

now,

$30 = 10 log(\dfrac{I_1}{10^{-12}})$

$\dfrac{I_1}{10^{-12}}= 10^3$

$I_1= 10^{-8}\ W/m^2$

to hear the whisper sound = 80 dB

$80 = 10 log(\dfrac{I_2}{10^{-12}})$

$\dfrac{I_2}{10^{-12}}= 10^8$

$I_2= 10^{-4}\ W/m^2$

we know intensity of sound is inversely proportional to square of distances

$\dfrac{I_1}{I_2}=\dfrac{r_2^2}{r_1^2}$

$\dfrac{10^{-8}}{10^{-4}}=\dfrac{r_2^2}{20^2}$

$10^{-4}=\dfrac{r_2^2}{20^2}$

r₂ = 0.2 m

6 0

3 years ago

The gauge pressure at the bottom of a cylinder of liquid is 0.30atm. The liquid is poured into another cylinder with twice the r

likoan [24]

Answer:

$P_g' = 0.075 atm$

Explanation:

Gauge pressure at the bottom of the cylinder depends on the height of water in the cylinder

So here we can say that

$P_g = \rho g h$

now when liquid is filled to height "h" in base area "A" then gauge pressure of the liquid at the bottom is given as

$P_g = 0.30 atm$

now we put the whole liquid into another cylinder with twice radius of the first cylinder

So area becomes 4 times

now by volume conservation we can say that if area is increased by 4 times then height of liquid will decrease by 4 times

so we have

$h' = \frac{h}{4}$

so gauge pressure is given as

$P_g' = \frac{0.30}{4} = 0.075 atm$

5 0

3 years ago

Two uniform solid cylinders, each rotating about its central (longitudinal) axis, have the same mass of 3.56 kg and rotate with

Natali5045456 [20]

Answer:

(a) 3107.98 J

(b) 14530.6 J

Explanation:

mass, m = 3.56 kg

angular speed, ω = 179 rad/s

Moment of inertia of solid cylinder, I = 1/2 mr^2

where, m is the mass and r be the radius of the cylinder.

(a) radius, r = 0.330 m

I = 0.5 x 3.56 x 0.330 x 0.330 = 0.194 kgm^2

The formula for the rotational kinetic energy is given by

$K = \frac{1}{2}I\omega ^{2}$

K = 0.5 x 0.194 x 179 x 179 = 3107.98 J

(b) radius, r = 0.714 m

I = 0.5 x 3.56 x 0.714 x 0.714 = 0.907 kgm^2

The formula for the rotational kinetic energy is given by

$K = \frac{1}{2}I\omega ^{2}$

K = 0.5 x 0.907 x 179 x 179 = 14530.6 J

3 0

3 years ago

Which factor affects elastic potential energy but not gravitational potential energy?

Vika [28.1K]

Answer:

The correct answer is the spring constant (k)

Explanation:

Elastic potential energy: Epe = ½ * k * Δx²

k = spring constant

Δx = displacement

Gravitational ptential energy: Ep = m*g*h

g = (acceleration due to gravity)

m = mass

h = relative height of an object to some reference point

3 0

3 years ago

Read 2 more answers

an instrument used a battery that provides 500 j of energy for 1200 seconds. what is the power of the instrument?

matrenka [14]

Answer: 0.42watts

Explanation:

Energy of the battery = 500 J

Time = 1200 seconds

Power of the instrument = ?

Recall that power is the rate of energy expended in doing work. Thus, power is energy expended divided by time taken.

i.e Power = (energy/time)

Power = 500J/1200 seconds

Power = 0.416 watts (Round to the nearest hundredth which is 0.42 watts)

Thus, the power of the instrument is 0.42watts

5 0

3 years ago