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DerKrebs [107]
3 years ago
10

How was Edwin Hubble able to use his discovery of Cepheids in Andromeda to prove that the "spiral nebulae" were actually galaxie

s external to the Milky Way?
Physics
1 answer:
Ad libitum [116K]3 years ago
7 0

Answer:  The correct answer is :  From the period-luminosity relation for Cepheids, he was able to determine the distance to Andromeda and show that it was far outside the Milky Way Galaxy.

Explanation:  Hubble's law says that the recession velocity of a galaxy is directly proportional to its distance from us. Hubble measured the distance to the Andromeda galaxy by applying the period-luminosity relationship to Cepheid.

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A weightlifter exerts an upward force on a 1000-N barbell and holds it at a height of 1 meter for 2 seconds. Approximately how m
Alex73 [517]

Amount of work done is zero and so power = 0 watts.

<u>Explanation:</u>

Power is the rate at which work is done, or W divided by delta t. Since the barbell is not moving, the weightlifter is not doing work on the barbell.Therefore, if the work done is zero, then the power is also zero.It may seem unusual that the data given in question is versatile i.e. A weightlifter exerts an upward force on a 1000-N barbell and holds it at a height of 1 meter for 2 seconds. But, still the answer is zero watts , this was a tricky question although conceptual basis of question was good! Power is dependent on amount of work done which is further related to displacement and here the net displacement is zero ! Hence, amount of work done is zero and so power = 0 watts.

6 0
3 years ago
Which term is defined by the force that moving, charged particles exert on one another?
Lisa [10]

Answer:

Electromagnetic force

Explanation:

There are four fundamental forces in nature:

- Gravity: it is the force that is exerted between any objects with mass. It is the weakest of all forces, so it is only relevant at planetary scales. It is always attractive, and it has an infinite range.

- Electromagnetic force: it is the force exerted between charged objects and between magnets (it is responsible for electric fields and magnetic fields). It is the 2nd strongest force, and it is the force that holds atoms in a molecule together. It can be attractive or repulsive, and it has an infinite range.

- Strong nuclear force: it is the strongest of all forces. It is responsible for holding the nucleons together inside the nucleus, and it is attractive. It has a very limited range (10^{-15}m), so it is relevant only at very small scales

- Weak nuclear force: it is the force responsible for radioactive decays and neutrino interactions. It also has a very short range (10^{-18} m

Looking at all these definitions, we see that the term that defines the force that acts between charged particles is the electromagnetic force.

7 0
3 years ago
Why does the chord of an electric heater not glow while the heating element does​
8_murik_8 [283]

Answer:

The heating element of the heater is made up of alloy which has very high resistance so when current flows through the heating element, it becomes too hot and glows red. But the resistance of cord which is usually of copper or aluminum is very low so it does not glow.

4 0
3 years ago
Can someone give me tips to passing AP Physics 1 with a solid A? Like, tips on how to memorize a lot of equations? Thank you!
Anna007 [38]
A good way for me to remember things is to study it, and to write it down! Say you want the formula for speed, I would write the formula multiple times on a piece of paper! 

Here's a video that I haven't actually watched, I just looked it up! It might help you out though: <span>https://www.youtube.com/watch?v=-Wqrw4G79Kc</span>
3 0
3 years ago
A 0.20 kg mass attached to the end of a spring causes it to stretch 3.0 cm. What is the spring constant? What is the potential e
SVEN [57.7K]

Given that the mass is m = 0.2 kg and the displacement is x = 3 cm = 0.03 m

We have to find the spring constant and potential energy.

The spring constant can be calculated by the formula

\begin{gathered} F=\text{ kx} \\ mg\text{ = kx} \\ k\text{ = }\frac{mg}{x} \end{gathered}

Here, k is the spring constant.

g = 9.8 m/s^2 is the acceleration due to gravity.

Substituting the values, the spring constant will be

\begin{gathered} k=\frac{0.2\times9.8}{0.03} \\ =\text{ 65.33 N/m } \end{gathered}

The potential energy can be calculated as

\begin{gathered} U=\frac{1}{2}kx^2 \\ =\frac{1}{2}\times65.33\text{ }\times(0.03)^2 \\ =\text{ 0.0293 J} \end{gathered}

8 0
1 year ago
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