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3 years ago

Which of the following is NOT a type (shape) of galaxy?

Physics

2 answers:

Setler [38]3 years ago

7 0

A. Triangular
This is not commonly found as a shape in a galaxy

kvv77 [185]3 years ago

6 0

Universe consists of billion of galaxies. There are four different shapes of galaxies which are commonly named as: Elliptical, Lenticular, spiral and irregular. Out of which spiral shaped galaxy is the most common. Spiral galaxies consists of small stars, Whereas the lenticular and the elliptical galaxies consists of largely composed matured stars.

Irregular galaxies have indeterminate shapes and is very small. Therefore, Galaxy have four different shapes which do not contain the shape of triangle. Hence, Triangular is not a shape of galaxy.

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Why is most space exploration accomplished with spacecraft that do not have astronauts on board

Olin [163]

Because of the enormous expense of creating conditions aboard
a spacecraft in which astronauts can survive, and the huge extra
weight and expense of guaranteeing their safety.

6 0

3 years ago

Read 2 more answers

Piano tuners tune pianos by listening to the beats between the harmonics of two different strings. When properly tuned, the note

Sophie [7]

(a) 2 Hz

The frequency of the nth-harmonic is given by

$f_n = n f_1$

where

$f_1$ is the fundamental frequency

Therefore, the frequency of the third harmonic of the A ( $f_1 = 440 Hz$ ) is

$f_3 = 3 \cdot f_1 = 3 \cdot 440 Hz =1320 Hz$

while the frequency of the second harmonic of the E ( $f_1 = 659 Hz$ ) is

$f_2 = 2 \cdot f_1 = 2 \cdot 659 Hz =1318 Hz$

So the frequency difference is

$\Delta f = 1320 Hz - 1318 Hz = 2 Hz$

(b) 2 Hz

The beat frequency between two harmonics of different frequencies f, f' is given by

$f_B = |f'-f|$

In this case, when the strings are properly tuned, we have

- Frequency of the 3rd harmonic of A-note: 1320 Hz

- Frequency of the 2nd harmonic of E-note: 1318 Hz

So, the beat frequency should be (if the strings are properly tuned)

$f_B = |1320 Hz - 1318 Hz|=2 Hz$

(c) 1324 Hz

The fundamental frequency on a string is proportional to the square root of the tension in the string:

$f_1 \propto \sqrt{T}$

this means that by tightening the string (increasing the tension), will increase the fundamental frequency also*, and therefore will increase also the frequency of the 2nd harmonic.

In this situation, the beat frequency is 4 Hz (four beats per second):

$f_B = 4 Hz$

And since the beat frequency is equal to the absolute value of the difference between the 3rd harmonic of the A-note and the 2nd harmonic of the E-note,

$f_B = |f_3-f_2|$

and $f_3 = 1320 Hz$ , we have two possible solutions for $f_2$ :

$f_2 = f_3 - f_B = 1320 Hz - 4 Hz = 1316 Hz\\f_2 = f_3 + f_B = 1320 Hz + 4 Hz = 1324 Hz$

However, we said that increasing the tension will increase also the frequency of the harmonics (*), therefore the correct frequency in this case will be

1324 Hz

8 0

2 years ago

Mass of object is 50g moves in a circular path of radius 10cm find work done

topjm [15]

Answer:

Work done = 0.3142 Nm

Explanation:

Mass of Object is 50 g

Circular path of radius is 10 cm ⇒ 0.1 m

Work done = Force × Distance = ?

*Distance moved (circular path) ⇒ Circumference of the circular path

2πr = 2 × 3.142 × 0.1 ⇒ 0.6284 m

*Force that is enough to move a 50 g must be equal or more than its weight.

therefore convert 50 grams to newton = 0.5 N

Recall that; work done is force times distance

∴ 0.5 N × 0.6284 m

Work done = 0.3142 Nm

3 0

2 years ago

A friend claims that throwing a baseball up towards the school roof illustrates gravitational potential energy transforming into

Cloud [144]

Answer:

The Statement is wrong because the reverse is the case as it is the kinetic energy that is being transformed to gravitational potential energy.

Explanation:

As your friend throws the baseball into the air the ball gains an initial velocity (u) and this makes the Kinetic energy to be equal to

$KE = \frac{1}{2} mu^2$

Here m is the mass of the baseball

Now as this ball moves further upward the that velocity it gained reduce due to the gravitational force and this in turn reduces the kinetic energy of the ball and this kinetic energy lost is being converted to gravitational potential energy which is mathematically represented as (m×g×h)

as energy can not be destroyed but converted to a different form according to the first law of thermodynamics

Looking a the formula for gravitational potential energy we see that the higher the ball goes the grater the gravitational potential energy.

4 0

3 years ago

While at the county fair, you decide to ride the Ferris wheel. Having eaten too many candy apples and elephant ears, you find th

Zepler [3.9K]

Answer:

$v=3.47m/s$

Explanation:

The speed is by definition the distance traveled divided over the time it takes to travel that distance. In this case, this distance is the circumference of the wheel, so we have:

$v=\frac{C}{t}=\frac{2\pi r}{t}$

where we have written the circumference in terms of its radius.

For our values we then obtain the value:

$v=\frac{2\pi r}{t}=\frac{2\pi (16m)}{(29s)}=3.47m/s$

5 0

3 years ago