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3 years ago

How was our galaxy formed?

Physics

1 answer:

Gala2k [10]3 years ago

8 0

Answer:

according to big bang theory our galaxy was formed 13billion years ago and then made the stars and galaxies we see today. ... The universe began as a very hot, small, and dense superforce (the mix of the four fundamental forces), with no stars, atoms, form, or structure (called a "singularity).

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3. A supersonic jet flying at 145 m/s experiences uniform acceleration at the rate of 23.1 m/s2 for 20.0 s.

mihalych1998 [28]

Answer:

A.607m/s | B.1.834Mach (speed of sound)

Explanation:

The plane's speed starts out at 145m/s, meaning after we calculate how many m/s it has accelerated, we must add that to the total.

If it accelerates for 20 seconds at a rate of 23.1m/s^2, this means that it accelerates 23.1m/s/s, or in words it gains 23.1 m/s every second. So, to calculate the gain in speed we simply multiply this by the duration of 20 seconds and get 462 m/s. Now, we add this to 145m/s, and get an end velocity of 607m/s.

For the plane's speed in terms of speed of sound, we divide 607m/s by the speed of sound, or 331m/s, and get ~1.834 Mach(speed of sound)

7 0

3 years ago

What happens to your behind when you sit for too long?

tino4ka555 [31]

Becomes numb. Or begins to hurt

5 0

3 years ago

Read 2 more answers

A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 4.00 m/s, and

igor_vitrenko [27]

Answer:

a) Her feet are in the air for 0.73+0.41 = 1.14 seconds

b) Her highest height above the board is 0.82 m

c) Her velocity when her feet hit the water is 7.16 m/s

Explanation:

t = Time taken

u = Initial velocity = 4 m/s

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

$v=u+at\\\Rightarrow 0=4-9.81\times t\\\Rightarrow \frac{-4}{-9.81}=t\\\Rightarrow t=0.41\ s$

$s=ut+\frac{1}{2}at^2\\\Rightarrow s=4\times 0.41+\frac{1}{2}\times -9.81\times 0.41^2\\\Rightarrow s=0.82\ m$

b) Her highest height above the board is 0.82 m

Total height she would fall is 0.82+1.8 = 2.62 m

$s=ut+\frac{1}{2}at^2\\\Rightarrow 2.62=0t+\frac{1}{2}\times 9.81\times t^2\\\Rightarrow t=\sqrt{\frac{2.62\times 2}{9.81}}\\\Rightarrow t=0.73\ s$

a) Her feet are in the air for 0.73+0.41 = 1.14 seconds

$v=u+at\\\Rightarrow v=0+9.81\times 0.73\\\Rightarrow v=7.16\ m/s$

c) Her velocity when her feet hit the water is 7.16 m/s

6 0

3 years ago

A certain microwave has a

Tatiana [17]

Answer:

$9.375\times 10^{9} Hz$

Explanation:

Frequency is mathematically defined as the quotient of speed divided by wavelength.

$Frequency= \frac {v}{W}$

where

v-is the speed of light

-w is wavelength.

Given the speed of the wave as $V=300000000 \ m/s$ and the wavelength $\lambda= 0.032\ m$ , we substitute these values in the Frequency function to solve for frequency:

$Frequency=\frac {300000000}{0.032}=9375000000 Hz=9.375\times 10^{9} Hz$

Hence, the wave's frequency is $9.375\times 10^9\ Hz$

5 0

3 years ago

Which situations might cause two observers (A and B) to measure different frequencies for the same vibrating object? Select the

Alex787 [66]

We want to explain why two different observes may measure different frequencies for the same vibrating object.

We will see that the two correct options are:

Observer A is stationary and Observer B is moving.
Observer A and Observer B are moving at different speeds relative to each other.

Let's assume that the vibrating object is a guitar string. Thus, the string makes a noise, and from that noise, we can estimate the frequency at which the string vibrates.

Now there appears a really cool effect, called the Doppler Effect. It says that the apparent change of frequency is due to the motion of the observer or the source of the frequency (or both).

For example, if you move towards the vibrating string, the perceived frequency will be larger, and you will hear a "higher" sound.

While if you move away from the string, the opposite happens, and you will hear a "lower" sound.

Then the only thing that impacts in how we perceive the frequency is our velocity relative to the source.

So, why do observers A and B measure different frequencies?

The two correct answers are:

Observer A is stationary and Observer B is moving.
Observer A and Observer B are moving at different speeds relative to each other.

If you want to learn more, you can read:

brainly.com/question/17107808

6 0

2 years ago