All categories

2 years ago

Choose all the answers that apply.

Physics

2 answers:

DerKrebs [107]2 years ago

7 0

Answer:

use their own matter to create nuclear reactions

generate their own energy

are classified primarily by temperature

usually seem bright if they are close to Earth

Explanation:

kvv77 [185]2 years ago

4 0

All of the answers are correct !!

You might be interested in

3) Magnets are used to separate steel cans from aluminum cans in recycling plants. How can

Elden [556K]

Answer:

Since steel contains iron (a magnetic metal), the magnets will attract the steel cans since aluminum is not magnetic. This is used to separate the steel cans from the aluminum cans so they can be recycled separately.

4 0

3 years ago

In addition to average weather conditions, climatological data also describes annual variations and fluctuations of temperature,

drek231 [11]

Answer:

In addition to average weather conditions, climatological data also describes annual variations and fluctuations of temperature, precipitation, wind speed and other variables.

Explanation:

A lot many observations are made all around the world regarding the weather each day. These observations and analysis are done by humans as well as automated instruments. The weather data is collected each day all year and any inaccuracies and discrepancies are checked and rectified. The results are later then presented as the climate data. There are various factors that are taken into consideration while determining the climate of a region. Apart from the factors that are already mentioned, wind speed is also one of the other variables.

8 0

3 years ago

determine the maximum angle theta for which the light rays incident on the end of the optical fiber of radius 1 mm are subhect t

Vesna [10]

Answer:

Explanation:

Let the critical angle be C .

sinC = 1 / μ where μ is index of refraction .

sinC = 1 /1.2

= .833

C = 56°

Then angle of refraction r = 90 - 56 = 34 ( see the image in attached file )

sin i / sinr = 1.2 , i is angle of incidence

sini = 1.2 x sinr = 1.2 x sin 34 = .67

i = 42°.

7 0

3 years ago

A spring with spring constant 15 N/m hangs from the ceiling. A ball is attached to the spring and allowed to come to rest. It is

olga nikolaevna [1]

Explanation:

It is given that,

Spring constant of the spring, k = 15 N/m

Amplitude of the oscillation, A = 7.5 cm = 0.075 m

Number of oscillations, N = 31

Time, t = 15 s

(a) Let m is the mass of the ball. The frequency of oscillation of the spring is given by :

$f=\dfrac{1}{2\pi}\sqrt{\dfrac{k}{m}}$

Total number of oscillation per unit time is called frequency of oscillation. Here, $f=\dfrac{31}{15}=2.06\ Hz$

$m=\dfrac{k}{4\pi^2f^2}$

$m=\dfrac{15}{4\pi^2\times 2.06^2}$

m = 0.0895 kg

m = 89 g

(b) The maximum speed of the ball that is given by :

$v_{max}=A\times \omega$

$v_{max}=A\times 2\pi f$

$v_{max}=0.075\times 2\pi \times 2.06$

$v_{max}=0.970\ m/s$

$v_{max}=97\ cm/s$

Hence, this is the required solution.

5 0

3 years ago

Assume the space shuttle's main engines produce 764,576 newtons of thrust, and the shuttle has a mass of 78,018 kg. Why does the

Nady [450]

Weight of anything = (mass) x (gravity in the place where the thing is)

Weight of anything on Earth = (mass) x (9.81 m/s²)

Weight of the shuttle = (78,018 kg) x (9.81 m/s²)

Weight of the shuttle, on Earth = 765,357 Newtons

Thrust of main engines = 764,576 Newtons

Are you starting to see the problem yet ?

The weight of the whole thing standing on the launch pad is 751 Newtons more than the maximum thrust of the main engines, and the engines can't lift it ! Even with all throttles wide open, the main engines alone would need about 175 more pounds of thrust to budge that load off the ground. Even with the pedal to the metal, with flame and smoke belching out and covering the whole launch complex, the shuttle would just sit there and never leave the pad.

Well, no. That's not exactly what would happen. As the fuel in the main monster fuel tank is burned, the weight decreases. So it would actually happen like this: After the man announced "Zero ! We have ignition ! All engine running !", the ship would just sit there on the pad ... at first. It would go nowhere and not even wiggle, UNTIL the first 175 pounds of fuel got burned without accomplishing anything. The ship would then be 175 pounds lighter. At that point, the weight would be exactly equal to the thrust of the main engines, and the vertical forces on the ship would be balanced. Then, as MORE fuel continued to be wasted and the weight continued to decrease, the main engines could just begin to lift the ship off the pad.

So the correct answer is choice-D . It tells the whole story, quicker than I can tell it.

4 0

3 years ago