All categories

3 years ago

Which of the following cannot be determined from the spectrum of a star?

Physics

1 answer:

morpeh [17]3 years ago

4 0

Answer:

From spectral lines astronomers can determine not only the element, but the temperature and density of that element in the star.

You might be interested in

A student uses a spring to launch a marble vertically in the air. The mass of the marble is

Fed [463]

Answer:

the maximum height reached by the marble is 11.84 m.

Explanation:

Given;

mass of the marble, m = 0.02 kg

extension of the string, x = 0.08 m

force applied to the string, F = 58 N

Apply the principle of conservation of energy;

elastic potential energy = gravitational potential energy

¹/₂fx = mgh

$h = \frac{Fx}{2mg} \\\\h = \frac{58 \ \times \ 0.08}{2 \ \times \ 0.02 \ \times \ 9.8} \\\\h = 11.84 \ m$

Therefore, the maximum height reached by the marble is 11.84 m.

5 0

3 years ago

What is the power generated by a 45 kg person who walks up a flight of 12 stairs, each 30 cm high, in 12 s?

Free_Kalibri [48]

The total distance covered by the person is 12 times the height of each stair:
$\Delta h=12 \cdot 30 cm=360 cm=3.60 m$

The work done by the person to climb the stairs is equal to the increase in his gravitational potential energy:
$W= \Delta U=mg \Delta h=(45 kg)(9.81 m/s^2)(3.60 m)=1589.2 J$

And therefore, the power generated by the person in 12 s is the work done divided by the time taken:
$P= \frac{W}{t}= \frac{1589.2 J}{12 s}=132.3 W$

So, the correct answer is B.

3 0

4 years ago

Two train whistles, and , each have a frequency of 392 Hz. is stationary and is moving toward the right (away from ) at a speed

trasher [3.6K]

Answer:

Part a)

f = 371.1 Hz

Part b)

f = 417.7 Hz

Part c)

beat frequency = 46.6 Hz

Explanation:

Part a)

Due to doppler's Effect the frequency of the sound heard by the train which is moving away from the observer is given as

$f_1 = f_0\frac{v + v_o}{v + v_s}$

$f_1 = 392(\frac{340 + 15}{340 + 35})$

$f_1 = 371.1 Hz$

Part b)

Now from the second train which is approaching the person we can say

$f_2 = f_0\frac{v - v_o}{v - v_s}$

$f_2 = 392(\frac{340 - 15}{340 - 35})$

$f_2 = 417.7 Hz$

Part c)

As we know that beat frequency is the difference in the frequency from two sources

$f_b = f_2 - f_1$

$f_b = 417.7 - 371.1 = 46.6 Hz$

8 0

3 years ago

Help please! Test tomorrow!

dlinn [17]

Earth distance to the Sun is about 40 times the Moon's distance from earth.

<u>Explanation:</u>

The Earth's distance from the Sun is about 93 million miles. When it expressed in Km, it is 150 million Km.
The Moon's distance from Earth is 238,855 miles. When it is 40 times then it will approximately equal to 93 million miles.
The Sun's distance from Venus is 67.237 million miles. The Sun's distance from mercury is 35.832 million miles.