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MrRa [10]
3 years ago
12

A graduate student has done a careful analysis of the spectrum of a star. While she has found lines from many elements, there wa

s not a trace of the element helium in the spectra she has been analyzing. From this she can now conclude:_______
Physics
1 answer:
disa [49]3 years ago
7 0

Explanation:

The lines in the spectra of star is due to absorption of light emitted by star by different elements  present in atmosphere of the star .

If some element is present in the outer atmosphere of he star , it will absorb a particular portion of light , for which there will be black line in the spectrum .

These are called Fraunhoffer's lines .

Now there is no such line at the place of Helium in the light spectrum . This means that Helium element is not present in the outer atmosphere of the star.

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Robb wants to win the next sled race. He asks for your advice. What would you tell him he should change in order to win? Explain
In-s [12.5K]

Answer: Start at the top of the hill.

Explanation:

The options include:

a. Start at the bottom of the hill.

b. Start at the top of the hill.

c. Start in the middle of the hill.

Sled racing is simply a winter dog sport racing. Since Robb wants to win the next sled race, the advice that'll be given to him is that he should start at the top of the hill.

Other options such as starting at the bottom of the hill or the middle of the hill are wrong.

5 0
3 years ago
You are an industrial engineer with a shipping company. As part of the package- handling system, a small box with mass 1.60 kg i
Kisachek [45]

Answer:

v = 0.84m/s, v(max)= 0.997m/s

Explanation:

Initial work done by the spring, where c is the compression = 0.28m:

W_s = \frac{1}{2}kc^2

Work lost to friction:

W_f =\mu mg(c-x)

Energy:

E = W_s-W_f=\frac{1}{2}kc^2 -\mu mg(c-x)=\frac{1}{2}mv^2+\frac{1}{2}kx^2

(a) Solve for v:

v=\sqrt{\frac{k}{m}(c^2-x^2)-2\mu g(c-x)}

(b) Solve \frac{dv}{dx}=0 for x:

\frac{dv}{dx}=\frac{\mu g-\frac{k}{m}x}{\sqrt{\frac{k}{m}(c^2-x^2)-2\mu g(c-x)}}

\frac{dv}{dx}=0 if:

\mu g-\frac{k}{m}x = 0

x_{max} = \frac{\mu gm}{k}

v_{max}=\sqrt{\frac{k}{m}c^2-2\mu gc+(\mu g)^2\frac{m}{k}}

6 0
3 years ago
This equation is known as the ideal gas law, and it can be used to predict the behavior of many gases at relatively low pressure
Masja [62]
The correct answer is 
<span>C) either the pressure of the gas, the volume of the gas, or both, will increase.

In fact, the ideal gas law can be written as
</span>pV=nRT
<span>where 
p is the gas pressure
V is its volume
n is the number of moles
R is the gas constant
T is the absolute temperature of the gas

We can see that if the temperature T increases, then the term on the right in the equation increases, therefore the term on the left should increase as well. In order for this to be possible, at least one between p and V should increase, or also both of them. Therefore, the correct answer is C.</span>
6 0
3 years ago
6. If a drag racer wins the final round of herrace by going an average speed of 320 m/sin 4.5 seconds, what distance did he cove
Ivan

We want to calculate the distance covered by the drag racer. Recall, the formula for calculating distance is expressed as

Distance = speed x time

From the information given,

speed = 320 m/s

time = 4.5 s

By substituting these values into the formula, we have

Distance = 320 m/s x 4.5s

s cancels out. We are left with m. Thus,

Distance = 1440m

4 0
1 year ago
The kinetic energy of a sliding block came from the:
patriot [66]

Answer:

Correct sentence: gravitational potential energy of the mass on the hook.

Explanation:

The mechanical energy of a body or a physical system is the sum of its kinetic energy and potential energy. It is a scalar magnitude related to the movement of bodies and to forces of mechanical origin, such as gravitational force and elastic force, whose main exponent is Hooke's Law. Both are conservative forces. The mechanical energy associated with the movement of a body is kinetic energy, which depends on its mass and speed. On the other hand, the mechanical energy of potential origin or potential energy, has its origin in the conservative forces, comes from the work done by them and depends on their mass and position. The principle of conservation of energy relates both energies and expresses that the sum of both energies, the potential energy and the kinetic energy of a body or a physical system, remains constant. This sum is known as the mechanical energy of the body or physical system.

Therefore, the kinetic energy of the block comes from the transformation in this of the gravitational potential energy of the suspended mass as it loses height with respect to the earth, keeping the mechanical energy of the system constant.

3 0
3 years ago
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