URGENT!! ILL GIVE

Physics help pleaseee

Ilia_Sergeevich [38]

Answer:

the first questions answer is- the pressure is the same (balanced) outside and inside the window.

the second questions answer is- the atmospheric pressure increases.

Explanation:

I hope that this is what you were looking for.

6 0

3 years ago

A football coach sits on a sled while two of his players build their strength by dragging the sled across the field with ropes.

Jobisdone [24]

Answer:

F=507.7N

Explanation:

According to Newton's second law:

$\sum F=m.a$

in this case, the football players need to drag the coach at a constant velocity, thus means with no acceleration, so:

$\sum F=0\\\\-F_f+F_p*cos(\theta)=0\\\\$

there are 20 degrees between the two ropes that means each player exerts a force 10 degrees from the zero reference.

$F_p=2*F\\\\F=\frac{1000N}{2*cos(10)}\\\\F=507.7N$

5 0

3 years ago

Which most likely indicate a chemical change has occurred ?

Allushta [10]

If a new substance suddenly appears that wasn't there originally,
then a chemical change has occurred.

Like for example, (this is the only example I can think of right now):

-- You leave your bicycle outside in the rain, and it gets wet, and
a few days later there's some rust on it.

-- You scrape off some of the rust, take it to school, give it to the
Chemistry teacher, and ask her to analyze it and tell you what it
is. Later that day, she tells you it's a substance called "Iron oxide".

-- Where did that come from ? There was no iron oxide there.
There was only iron in the bicycle, and air, and water.

-- The iron oxide formed from a chemical change when the iron
on the surface of the bike combined with some of the oxygen in
the air, and molecules of a new substance were created. (For
some reason, the presence of water makes this chemical reaction
go faster.)

5 0

3 years ago

An AC circuit has an RMS voltage of 80 VAC. What's the circuit's average voltage?

yaroslaw [1]

-- The RMS value of an AC waveform is (1/2)(√2) x (peak value)

So the peak value is (√2) x (RMS value)

-- The Average value of an AC waveform is (2/π) x (peak value)

So the peak value is (π/2) x (Average value).

-- So far, this is all very entertaining, but how does it help us answer the question.

Well, we found the peak value in terms of the RMS and in terms of the Average. So we can set these equal to each other, and solve for the Average in terms of the RMS. This sounds like such a good plan, I think I'll do it !

Peak = (√2) x (RMS value) and Peak also = (π/2) x (Average value).

So (√2) · RMS = (π/2) · Average .

Divide each side by π : (√2) · RMS / π = (1/2) · Average

Multiply each side by 2 : Average = (2/π) · (√2) · RMS .

You said that the RMS value is 80 V, so

Average = (2/π) · (√2) · (80)

Average = (2 · √2 / π) · (80)

Average = 160√2 / π

Average = 72 volts . (But be sure to read the 'gotcha' below.)

Now I'll go ahead and tell you the 'gotcha':

All of these numbers are true, as far as they go. But the 'average' is only true for 1/2 cycle of an AC wave. Picture an AC wave in your mind. You'll see that it spends just as much time being negative as it spends being positive. So the 'average' of any number of AC whole cycles is zero.

7 0

3 years ago

A proton that has a mass m and is moving at +164 m/s undergoes a head-on elastic collision with a stationary carbon nucleus of m

Irina18 [472]

The concept of this problem is the Law of Conservation of Momentum. Momentum is the product of mass and velocity. To obey the law, the momentum before and after collision should be equal:

m₁ v₁ + m₂v₂ = m₁v₁' + m₂v₂', where
m₁ and m₂ are the masses of the proton and the carbon nucleus, respectively,
v₁ and v₂ are the velocities of the proton and the carbon nucleus before collision, respectively,
v₁' and v₂' are the velocities of the proton and the carbon nucleus after collision, respectively,

m(164) + 12m(0) = mv₁' + 12mv₂'
164 = v₁' + 12v₂' --> equation 1

The second equation is the coefficient of restitution, e, which is equal to 1 for perfect collision. The equation is

(v₂' - v₁')/(v₁ - v₂) = 1
(v₂' - v₁')/(164 - 0) = 1
v₂' - v₁'=164 ---> equation 2

Solving equations 1 and 2 simultaneously, v₁' = -138.77 m/s and v₂' = +25.23 m/s. This means that after the collision, the proton bounced to the left at 138.77 m/s, while the stationary carbon nucleus move to the right at 25.23 m/s.

7 0

3 years ago