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3 years ago

What is the name for a star and planets held together by gravity? A. solar system B. galaxy C. black hole D. supernova

Physics

1 answer:

DaniilM [7]3 years ago

5 0

These answers aren´t valid .

The correct answer will be:

Planetary system.

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What is the ratio of the intensities of an earthquake P wave passing through the Earth and detected at two points 14 km and 49 k

Molodets [167]

Answer:

$\dfrac{I_1}{I_2}=12.25$

Explanation:

$r_1$ = 14 km

$r_2$ = 49 km

Intensity of a wave is inversely proportional to distance

$I\propto \dfrac{1}{r^2}$

So,

$\dfrac{I_1}{I_2}=\dfrac{r_2^2}{r_1^2}\\\Rightarrow \dfrac{I_1}{I_2}=\dfrac{49^2}{14^2}\\\Rightarrow \dfrac{I_1}{I_2}=12.25$

The ratio of the intensities is $\dfrac{I_1}{I_2}=12.25$

6 0

3 years ago

For what absolute value of the phase angle does a source deliver 71 % of the maximum possible power to an RLC circuit

kherson [118]

Answer: the absolute value of the phase angle is 28°

Explanation:

taking a look at expression for the instantaneous electric power in an AC circuit;

P = VI -------let this be equation 1

p is power, v is voltage and I is current;

for maximum power

P_max = V_rms × I_rms --------let this be equ 2

where P_max is the maximum power, V_rms is the rms value of voltage and I_rms is the rms value of current.

Also for average electric power in an AC circuit

P_avg = V_rms × I_rms × cos²∅ -------let this be equ 3

where P_avg is the average power and cos∅ is the power factor

now from equation 2; P_max = V_rms × I_rms

so p_max replaces V_rms × I_rms in equation 3

we now have

P_avg = P_max × cos²∅

so we substitute

expression for the given value of the average power is

P_avg = P_max × 75%

p_avg = P_max.78/100

for the expression of the average electricity in an AC circuit

P_max.78/100 = P_max × cos²∅

78/100 = cos²∅

to get the absolute value of phase angle

∅ = cos⁻¹ ( √(78/100))

∅ = cos⁻¹ ( 0.8832)

∅ = 27.969 ≈ 28°

Therefore the absolute value of the phase angle is 28°

8 0

2 years ago

Calculate the acceleration of a bus that goes

Svet_ta [14]

The acceleration of the bus is 1.11 meters per second square to the direction of motion

Explanation:

Acceleration is the rate of change of velocity

The formula of the acceleration is $a=\frac{v_{2}-v_{1}}{t}$ , where

$v_{1}$ is the initial velocity

$v_{2}$ is the final velocity
t is the time

A bus that goes from 10 km/h to a speed of 50 km/h in 10 seconds

→ $v_{1}$ = 10 km/h

→ $v_{2}$ = 50 km/h

→ t = 10 seconds

Change the unite of the time from seconds to hour

→ 1 hour = 60 × 60 = 3600 seconds

→ 10 seconds = $\frac{10}{3600}=\frac{1}{360}$ hour

Substitute these values in the formula of the acceleration above

→ $a=\frac{50-10}{\frac{1}{360}}$

→ a = 14400 km/h²

To change the unit of acceleration to meter per second change the

kilometer to meter and the hour to seconds

→ 1 km = 1000 m

→ 1 hour = 3600 seconds

→ $a=\frac{14400*1000}{(3600)^{2}}=\frac{10}{9}$

→ a = 1.11 m/sec².

The acceleration of the bus is 1.11 meters per second square to the direction of motion

Learn more:

You can learn more about the acceleration in brainly.com/question/6323625

#LearnwithBrainly

4 0

3 years ago

A student is performing experiments on a particular substance. Which

boyakko [2]

Answer: A.

Explanation:

6 0

2 years ago

Mass (kg)

Tju [1.3M]

Mass.

Because mass doesn't depend on weight but weight depends on mass.

8 0

3 years ago

Read 2 more answers