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siniylev [52]
3 years ago
6

Why do reflecting telescopes usually have a secondary mirror in addition to a primary mirror?

Physics
1 answer:
Gemiola [76]3 years ago
8 0
Once the starlight or moonlight comes down the tube and hits the big main mirror at the bottom, it's reflected, and heads back up the tube, along the same way it came in. But if you're looking through an eyepiece, the eyepiece is on the SIDE of the tube. So you need another small mirror, to catch the focused light before it goes up out of the tube, and send it sideways to the eyepiece.
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Which of the following would increase the elastic force acting on that object
olga_2 [115]

Answer:

Which of the following would increase the elastic force acting on that object? Moving a spring to an unstretched position. Compressing a spring twice as much as its starting position.

Explanation:

4 0
3 years ago
Read 2 more answers
Two point charges each have a value of 3.0 c and are separated by a distance of 4.0 m. what is the electric field at a point mid
swat32
 <span>Place a test charge in the middle. It is 2cm away from each charge. 
The electric field E= F/Q where F is the force at the point and Q is the charge causing the force in this point. 
The test charge will have zero net force on it. The left 30uC charge will push it to the right and the right 30uC charge will push it to the left. The left and right force will equal each other and cancel each other out. 
THIS IS A TRICK QUESTION. 
THe electric field exactly midway between them = 0/Q = 0. 
But if the point moves even slightly you need the following formula 
F= (1/4Piε)(Q1Q2/D^2) 
Assume your test charge is positive and make sure you remember two positive charges repel, two unlike charges attract. Draw the forces on the test charge out as vectors and find the magnetude of the force, then divide by the total charge to to find the electric field strength:)</span>
4 0
3 years ago
Galois drove 60.0 kilometers due west in 5.00 hours and then drove 43.0 kilometers due north in 3.00 hours.
IceJOKER [234]

Answer:

Explanation:

See the attachment for the details.  A right triangle is formed to find the hypotenuse of the two legs consisting of the actual driving distances and times.  The hypotenuse gives the vector information for the displacement at the end of 8 hours of driving.  

The individual driving times and distances are summed to provide:

(<u>a) How far did he travel?</u>

103 km

<u>(b) What was his average speed?</u>

12.88 km/h

<u>(c) What was his displacement?</u>

73.82 km

<u>(d) What was his average velocity?</u>

9.228 km/h

8 0
3 years ago
A Red-Tailed Hawk leaves its nest and flies 100.0 meters across the sky in 20 seconds, when it spots a garter snake on the groun
igomit [66]
Speed = distance / time.

Speed of him leaving the nest:
S = 100 / 20sec

5 m/s.

Catching the snake:
S2 = 50 / 5sec

10 m/s.

Average of 5& 10 = 7.5

7.5 m/s has to be the answer.
3 0
3 years ago
A bottle dropped from a balloon reaches the ground in 20 s. determine the height of the balloon if (a) it was at rest in the air
romanna [79]
<span>a) 1960 m b) 960 m Assumptions. 1. Ignore air resistance. 2. Gravity is 9.80 m/s^2 For the situation where the balloon was stationary, the equation for the distance the bottle fell is d = 1/2 AT^2 d = 1/2 9.80 m/s^2 (20s)^2 d = 4.9 m/s^2 * 400 s^2 d = 4.9 * 400 m d = 1960 m For situation b, the equation is quite similar except we need to account for the initial velocity of the bottle. We can either assume that the acceleration for gravity is negative, or that the initial velocity is negative. We just need to make certain that the two effects (falling due to acceleration from gravity) and (climbing due to initial acceleration) counteract each other. So the formula becomes d = 1/2 9.80 m/s^2 (20s)^2 - 50 m/s * T d = 1/2 9.80 m/s^2 (20s)^2 - 50m/s *20s d = 4.9 m/s^2 * 400 s^2 - 1000 m d = 4.9 * 400 m - 1000 m d = 1960 m - 1000 m d = 960 m</span>
6 0
4 years ago
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