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labwork [276]
3 years ago
9

Which of the following would most likely be an example of a mass-transit disaster?

Physics
1 answer:
Aleonysh [2.5K]3 years ago
7 0

Answer:

i think it is c if not im sorry if im wrong

Explanation:

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The loudness of a sound is the waves amplitude <br><br><br><br> True or false
kakasveta [241]

Answer:

true i think

Explanation:

The amplitude of a sound wave determines its loudness or volume. A larger amplitude means a louder sound, and a smaller amplitude means a softer sound. In Figure 10.2 sound C is louder than sound B. The vibration of a source sets the amplitude of a wave.

4 0
3 years ago
Read 2 more answers
At an altitude of 5000 m the rocket's acceleration has increased to 6.9 m/s2 . What mass of fuel has it burned?
sergey [27]

1) Initial upward acceleration: 6.0 m/s^2

2) Mass of burned fuel: 0.10\cdot 10^4 kg

Explanation:

1)

There are two forces acting on the rocket at the beginning:

- The force of gravity, of magnitude F_g = mg, in the downward direction, where

m=1.9\cdot 10^4 kg is the rocket's mass

g=9.8 m/s^2 is the acceleration of gravity

- The thrust of the motor, T, in the upward direction, of magnitude

T=3.0\cdot 10^5 N

According to Newton's second law of motion, the net force on the rocket must be equal to the product between its mass and its acceleration, so we can write:

T-mg=ma (1)

where a is the acceleration of the rocket.

Solving for a, we find the initial acceleration:

a=\frac{T-mg}{m}=\frac{3.0\cdot 10^5-(1.9\cdot 10^4)(9.8)}{1.9\cdot 10^4}=6.0 m/s^2

2)

When the rocket reaches an altitude of 5000 m, its acceleration has increased to

a'=6.9 m/s^2

The reason for this increase is that the mass of the rocket has decreased, because the rocket has burned some fuel.

We can therefore rewrite eq.(1) as

T-m'g=m'a'

where

m' is the new mass of the rocket

Re-arranging the equation and solving for m', we find

m'=\frac{T}{g+a}=\frac{3.0\cdot 10^5}{9.8+6.9}=1.8\cdot 10^4 kg

And since the initial mass of the rocket was

m=1.9 \cdot 10^4 kg

This means that the mass of fuel burned is

\Delta m = m-m'=1.9\cdot 10^4 - 1.80\cdot 10^4 = 0.10\cdot 10^4 kg

3 0
3 years ago
By increasing the circuits resistance R, in a capacitive circuit the phase difference between the current in the circuit and pot
oksian1 [2.3K]

Answer:

B) Gets smaller

Explanation:

The difference of phase between current and voltage in a AC circuit is the phase  angle and it depends on the value of Z ( circuit impedance)

Z = R + X   where R is the resistive component and X the reactance component, which is due either to a presence of an  inductor or a capacitor. In any case the total impedance depends on R the resistive, and the phase angle φ is:  

tan⁻¹ φ =  X/R

Have a look to a pure capactive circuit (we are talking about AC current) in this case current leads voltage by 90⁰. If we add a resistor in the circuit  the current still will lead a voltage but in this condition the phase angle will be smaller,

If  R increase, X/R  decrease and tan⁻¹ φ also decrease

7 0
3 years ago
A 425-g piece of metal at 100°C is dropped into a 100-g aluminum cup containing 500 g of water at 15°C. The final temperature of
yKpoI14uk [10]

The specific heat of the metal, assuming no heat is exchanged with the surroundings is 2140 J/(kg•K).

<h3>Specific heat capacity of the metal</h3>

The specific heat capacity of the metal is determined from the principle of conservation of energy.

energy lost by the metal = energy gained by aluminum + energy gained by water

Q = mcΔθ

where;

  • m is mass (kg)
  • c is specific heat capacity
  • Δθ is change in temperature

0.425c(100 - 40) = 0.1(900)(40 - 15) + 0.5(4186)(40 - 15)

25.5c = 2250 + 52,325

c = 54,575/25.5

c = 2140 J/(kg•K)

Learn more about specific heat capacity here: brainly.com/question/21406849

#SPJ1

5 0
1 year ago
Discuss the production, transmission, and usage of electricity in the context of conservation of energy. When electricity is “us
mr Goodwill [35]

There are huge losses in the transmission, production and usage of electricity and the reduction of these losses in order to save electricity is called as conservation of energy.

As per the statistics, there is loss of nearly 4% while the transmission of electricity. Like wise during production also, lot of electricity get wasted due to the inefficient material used. None of the production material nor the equipment used have 100% efficiency and thus there is always a possibility of energy wastage.

When it is said that the energy is wasted , it simply means that the energy production which should have been 100% as per calculation is not completely derived from the source due to the inefficient conversion process. For example, a turbine while rotating must convert 100 % of the water energy or water falling on it into electrical energy but the turbine is not able to do so as some of the water is lost or its energy is lost before conversion while going through the mechanical process.

3 0
3 years ago
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