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3 years ago

Pls hurry, i'm timed TmT

Physics

2 answers:

solong [7]3 years ago

5 0

According to the introduction, why are black holes invisible?

the answer is in the first paragraph :)

"Black holes are invisible because they have so much gravity that nothing escapes. Not even light can escape or bounce off."

hope this helped !

Savatey [412]3 years ago

5 0

Answer:

Answer is C. They have so much gravity that nothing escapes.

Explanation:

it's in the first paragraph

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What is the newton first, second, third law of motion/

ozzi

Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force.

Newton's second law of motion pertains to the behavior of objects for which all existing forces are not balanced.

Newton's third law is: For every action, there is an equal and opposite reaction.

6 0

4 years ago

A high-speed train travels 480 km from Paris to Grenoble, France, at an average speed of 180 km/h. How long will it take to reac

hichkok12 [17]

The time (t) it will take for the train to reach to Grenoble is the quotient when the distance (d) is divided by the speed (s). That is,
t = d / s
Substituting the known values,
t = 480 km / 180 km/h
t = 2.667 h
Thus, it will take approximately 2.7 h to reach Grenoble. The answer is letter D.

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3 years ago

Calculate the ratio of the drag force on a jet flying at 1190 km/h at an altitude of 7.5 km to the drag force on a prop-driven t

Bond [772]

Answer:

$\frac{D_{jet}}{D_{prop}}=2.865$

Explanation:

Given data

Speed of jet Vjet=1190 km/h

Speed of prop driven Vprop=595 km/h

Height of jet 7.5 km

Height of prop driven transport 3.8 km

Density of Air at height 10 km p7.8=0.53 kg/m³

Density of air at height 3.8 km p3.8=0.74 kg/m³

The drag force is given by:

$D=\frac{1}{2}CpAv^2\\$

The ratio between the drag force on the jet to the drag force on prop-driven transport is then given by:

$\frac{D_{jet}}{D_{prop}}=\frac{(1/2)Cp_{7.5}Av_{jet}^2}{1/2)Cp_{3.8}Av_{prop}^2} \\\frac{D_{jet}}{D_{prop}}=\frac{p_{7.5}v_{jet}^2}{p_{3.8}v_{prop}}\\\frac{D_{jet}}{D_{prop}}=\frac{(0.53)(1190)^2}{(0.74)(595)^2}\\ \frac{D_{jet}}{D_{prop}}=2.865$

4 0

3 years ago

two parallel plates of area 5.68*10^-4 m^2 have equal and opposite charges of 8.38*10^-11 C placed on them. what is the electric

shutvik [7]

Answer: unit n/c

Explanation: This should be the answer because I just asked my Physics Teachers I hope this is correct

Hope This Helps :)

4 0

3 years ago

Read 2 more answers

The speed of sound at sea level is normally about 340 m/s. A stationary fire alarm has a frequency of 15,000 Hz. An observer run

Musya8 [376]

Answer:

The velocity of the observer is 6.8 m/s

Explanation:

Doppler effect equation is given by the formula:

$f'=\frac{v+v_o}{v-v_s} f\\\\where\ f'\ is \ the\ observed \ frequency=15300\ Hz,v_o\ is\ the\ velocity\ of\ the\ observer,\\v_s\ is\ the\ velocity\ of \ source=0,v\ is\ the\ velocity\ of\ sound=340\ m/s\ and\ f\ is\ actual\\frequency=15000\ Hz.\\\\substituting:\\\\15300=15000(\frac{340+v_o}{340} )\\\\340+v_o=346.8\\\\v_o=6.8\ m/s$ The velocity of the observer is 6.8 m/s

3 0

3 years ago