PHYSICS HIGH SCHOOL

_______ discovered that there were other galaxies besides the Milky Way.A. Albert Einstein
B. Edwin Hubble
C. Galilei Galileo
D. Sir Isaac Newton

Answers

Answer 1
Answer:    Edwin Hubble discovered that there were other galaxies besides the milky way. 
Answer 2
Answer:
Edwin Hubble discovered there were other galaxies besides the Milky Way.

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Value that is measured by the slope of a position-time graph

Answers

The slope is the change in y over change in x.
In a position vs time graph, the position is the y-axis, and the time is the x-axis.
So the slope would be position over time. Position is a distance. So the slope is distance/time, which is velocity.
And also looking at units, distance is in meters (m), and time is in seconds (s). The unit m/s is a unit for velocity.

How do wind turbines pollute their environment?

Answers

Although the wind turbines do not pollute the environment directly, it is still able to pollute the environment indirectly. The maintenance, construction, and the assembly of the wind turbines would make use of equipment or machines that would emit some harmful substances. For example, the delivery of the materials, the turbine parts, and the other equipment would entail a lot of back and forth trips. The deliverer, from his vehicle, would sometimes emit smoke or gas from his vehicle that is dangerous to health. 
Wind turbines in fact to pollute the environment. They pollute the environment because when they are being built or manufactured, pollution is produced. Wind power does produce pollution. It also takes up space in land. In farms they take up a lot of space so then we cannot grow crops and animals cannot live there. One turbine can give electricity to about 400 homes. Imagine how many you will need to power a whole country! The turbines are also very loud. It can damage peoples ears when they are near one.

What is the closest distance you should live from the airport runway to preserve your peace of mind?

Answers

At least one in a half to a mile a way

A hot air balloon is moving vertically upwards at a velocity of 3m/s. A sandbag is dropped when the balloon reaches 150m. How long does the sandbag take to reach the ground and what is the maximum height it reaches?

Answers


This is a perfect opportunity to stuff all that data into the general equation for the height of an object that has some initial height, and some initial velocity, when it is dropped into free fall.

                       H(t)  =  (H₀)  +  (v₀ T)  +  (1/2 a T²)

 Height at any time 'T' after the drop =

                          (initial height) +
                                              (initial velocity) x (T) +
                                                                 (1/2) x (acceleration) x (T²) .

For the balloon problem ...

-- We have both directions involved here, so we have to define them:

     Upward  = the positive direction

                       Initial height = +150 m
                       Initial velocity = + 3 m/s

     Downward = the negative direction

                     Acceleration (of gravity) = -9.8 m/s²

Height when the bag hits the ground = 0 .

                 H(t)  =  (H₀)  +  (v₀ T)  +  (1/2 a T²)

                   0    =  (150m) + (3m/s T) + (1/2 x -9.8 m/s² x T²)

                   -4.9 T²  +  3T  + 150  =  0

Use the quadratic equation:

                         T  =  (-1/9.8) [  -3 plus or minus √(9 + 2940)  ]

                             =  (-1/9.8) [  -3  plus or minus  54.305  ]

                             =  (-1/9.8) [ 51.305  or  -57.305 ]

                          T  =  -5.235 seconds    or    5.847 seconds .

(The first solution means that the path of the sandbag is part of
the same path that it would have had if it were launched from the
ground 5.235 seconds before it was actually dropped from balloon
while ascending.)

Concerning the maximum height ... I don't know right now any other
easy way to do that part without differentiating the big equation.
So I hope you've been introduced to a little bit of calculus.

                    H(t)  =  (H₀)  +  (v₀ T)  +  (1/2 a T²)

                   H'(t)  =  v₀ + a T

The extremes of 'H' (height) correspond to points where h'(t) = 0 .

Set                                  v₀ + a T  =  0

                                      +3  -  9.8 T  =  0

Add 9.8 to each  side:   3               =  9.8 T

Divide each side by  9.8 :   T = 0.306 second

That's the time after the drop when the bag reaches its max altitude.

Oh gosh !  I could have found that without differentiating.

- The bag is released while moving UP at 3 m/s .

- Gravity adds 9.8 m/s of downward speed to that every second.
So the bag reaches the top of its arc, runs out of gas, and starts
falling, after
                       (3 / 9.8) = 0.306 second .

At the beginning of that time, it's moving up at 3 m/s.
At the end of that time, it's moving with zero vertical speed).
Average speed during that 0.306 second = (1/2) (3 + 0) =  1.5 m/s .

Distance climbed during that time = (average speed) x (time)

                                                           =  (1.5 m/s) x (0.306 sec)

                                                           =  0.459 meter  (hardly any at all)

     But it was already up there at 150 m when it was released.

It climbs an additional 0.459 meter, topping out at  150.459 m,
then turns and begins to plummet earthward, where it plummets
to its ultimate final 'plop' precisely  5.847 seconds after its release.  

We can only hope and pray that there's nobody standing at
Ground Zero at the instant of the plop.

I would indeed be remiss if were to neglect, in conclusion,
to express my profound gratitude for the bounty of 5 points
that I shall reap from this work.  The moldy crust and tepid
cloudy water have been delicious, and will not soon be forgotten.

To practice Problem-Solving Strategy 3.2 Relative velocity. An airplane pilot wishes to fly directly westward. According to the weather bureau, a wind of 75.0 km/hour is blowing southward. The speed of the plane relative to the air (called the "air speed") as measured by instruments aboard the plane is 310 km/hour . In which direction should the pilot head?

Answers

The pilot should head 13.6° north of west.

Why?

We can solve the problem by using trigonometric relations. Since there is a right triangle formed between the direction that the pilot wants to fly to and the wind's speed, we can use the following formula:

Tan(\alpha )=(WindSpeed)/(PlaneSpeed)\n\n\alpha =Tan((WindSpeed)/(PlaneSpeed))^(-1)=ArcTan((WindSpeed)/(PlaneSpeed))\n\n\alpha =ArcTan((WindSpeed)/(PlaneSpeed))

Now, substituting the given information and calculating, we have:

Wind=75(km)/(m) (southward)\n\nAirplane=310(km)/(h)

\alpha =ArcTan((WindSpeed)/(PlaneSpeed))\n\n\alpha =(75(km)/(h) )/(310(km)/(h) )=13.6\°

Hence, we have that the pilot should head to 13.6° north of west.

Have a nice day!

Evelyn learns that a sound wave can be recorded electronically as an analog signal or as a digital signal. She investigates these two signal types. She records her voice using a tape recorder, which uses an analog signal to produce sound when played back. She also records her voice using a computer, which uses a digital signal to produce sound when played back. Evelyn replays each recording 100 times.a. Describe a difference that Evelyn would most likely hear between the two recordings after being replayed 100 times.

b. Explain why the two recordings would sound different after being replayed 100 times.

Answers

a)The analog signal'spitch and frequency change each time. It is continuous in the digital signal.

What is the digital signal?

A digital signal is one in which data is represented as a series of discrete numbers.

To reduce the influence of noise in communication, a digital signal is utilized. When compared to analog signals, digital signals convey more information per unit of time.

a)Evelyn would most likely notice a difference between the two recordings after hearing them 100 times is that the analogsignal's pitch and frequency change each time. It is continuous in the digital signal.

b)After 100 replays, the two recordings would sound different since the digital signal has a greater quality throughout long-distance transmission.

When digital signals are transferred, the amount of bandwidth used is lowered.

Hence, the digital signal has a greater quality throughout long-distance transmission causing two recordings would sound different.

To learn more about digital signals refer to:

brainly.com/question/14825566

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