Physics College

## Answers

**Answer 1**

In terms of what you'd see, an atom in the ground state wouldn't emit any light because all the orbital electrons are in their lowest possible energies in the atom.

A ground state atom has its orbiting electrons all in their lowest energy states consistent with, I think, the Pauli (nobel prize winner) exclusion principle and Hund's rules.An excited state atom has one or more electrons in higher energy states - say by thermal agitation (heating them). When these electrons "de excite" back to a lower energy level, they emit electromagnetic radiation in the form of photons. With the correct energy/frequency the photons are visible as a spectrum.

## Related Questions

A rock is dropped from a sea cliff and hits the water 3.2s later. How high is the cliff? How long would it take sound to travel the same distance? How long would it take light to travel this distance? Show work!

### Answers

A rock is dropped from a sea cliff and hits the water 3.2s later. How high is the cliff?

t = sqrt(2y/g)

3.2 = sqrt(2y/9.81)

y = 50.23 m

How long would it take sound to travel the same distance?

t = 50.23 /343 m/s

t = 0.15 s

How long would it take light to travel this distance?

t = 50.23 /299792458 m / s

t = 1.68x10^-7 s

A body A of mass 1.5kg, travelling along the positive x-axis with speed 4.5m/s, collides with another body B of mass 3.2kg which, initially, is at rest. As a result of the collision, A is deflected and moves with a speed 2.1m/s in a direction which is at angle 30° below the x-axis. B is set in motion at an angle θ above the x-axis. Calculate the velocity of B after the collision

### Answers

We consider the momentum in the x-direction and apply the principle of conservation of momentum to form the equation:

m(A)u(A) = m(A)v(A) + m(B)v(B), since u(B) = 0 as B is at rest

We calculate v(A) using:

Vx = Vcos∅

Vx = 2.1cos(30)

Vx = 1.82 m/s

1.5 x 4.5 = 1.5 x 1.82 + 3.2v(B)

v(B) = 1.26 m/s

The deflection angle of B will be 30° above the positive x-axis, so:

v(B) = Vcos∅

V = 1.26 / cos(30)

V = 1.45 m/s

The velocity of B is 1.45 m/s

A missile is moving 1350 m/s at a 25.0 angle

### Answers

I will answer both versions assuming what you want to know is the distance it travels up from and over the ground. and how long until it reaches space. 540 meters per second up and over. to reach space which is 100km above sea level, it would take about 5400 minutes

1. The gravitational force acting on a falling body and its weight is constant. But the law of universal gravitation tells us that the gravitational force on a body increases as it gets closer to Earth’s center. Is there a contradiction here?

### Answers

It's not so much a "contradiction" as an approximation. Newton's law of gravitation is an inverse square law whose range is large. It keeps people on the ground, and it keeps satellites in orbit and that's some thousands of km. The force on someone on the ground - their weight - is probably a lot larger than the centripetal force keeping a satellite in orbit (though I've not actually done a calculation to totally verify this). The distance a falling body - a coin, say - travels is very small, and over such a small distance gravity is assumed/approximated to be constant.

Suppose you balance a 2.4 kg ball on the tip of your finger, which has an area of 1.4 cm squared? Find the pressure on your finger.

### Answers

P=F/A

a.Force=mg

= 2.4Kg(9.8m/s^2)

= 23.52 N

b. P=F/A

= (23.52 N)/(1.4 cm^2)

= 16.8 Pa

Point charge 3.5 μC is located at x = 0, y = 0.30 m, point charge -3.5 μC is located at x = 0 y = -0.30 m. What are (a)the magnitude and (b)direction of the total electric force that these charges exert on a third point charge Q = 4.0 μC at x = 0.40 m, y = 0?

### Answers

Hi, thank you for posting your question here at Brainly.

To solve this problem, we use Coulomb's Law:

F = kQ1Q2/d^2, where k = 9x10^9

Q1 = 3.5 uC

Q2 = -3.5 uC

Q3 = 4.0 uC

But first, we find the distance between Q1 and Q3 and between Q2 and Q3.

d between Q1 and Q2:

d = sqrt[(0-0.4)^2+(0.3-0)^2]

d = 0.5 m

d between Q1 and Q3:

d = sqrt[(0-0.4)^2+(-0.3-0)^2]

d = 0.5 m

Through force balance, F between Q2 and Q3 - F between Q1 and Q3:

Thus, the net force is -1 x 10^-12 C

What is the definition of resistance in physics,and science???

### Answers

Aforce,suchasfriction,thatoperatesopposite the direction of motion of a body and tendsto preventorslowdownthebody'smotion.

Hope this Helps! :)

A copper Wire has a length of 160 m,and a diameter of 1.0 mm,if ,the wire is connected to a 1.5-Volt battery ,How much Current flows through the wire?????

### Answers

Some guidance notes which may help.To calculate the current flow, Ohm's law can be used. This can be written as current=voltage/resistance, or I=V/R. V is 1.5V.R for the copper wire quoted would be calculated as R = resistivity x length/cross sectional area. The area would be calculated from the formula area = pi x diameter squared/4So, R=resistivity x length divided by (pi x diameter squared/4)Until is the resistivity of copper is known, that's about as far as can be gone.Any further questions, please ask.

May someone please help me with this The ability to perceive accurately, appraise, and express emotion is called emotional reasoning.

emotional intelligence.

emotional logic.

emotional integrity.

### Answers

Hello there.

May someone please help me with this The ability to perceive accurately, appraise, and express emotion is called

emotional intelligence.

B.)The ability to perceive accurately, appraise, and express emotion is called "Emotional Intelligence"

Hope this helps!

The recommended daily allowance (RDA) of the trace metal magnesium is 410 mg/day for males. Express this quantity in μg/day.

### Answers

410,000 micrograms/day, I think

In constructing a moral argument, the point is to A.

come to a conclusion that leads to reasonable action consistent with moral values.

B.

clarify your own stage of moral reasoning.

C.

identify more prescriptive than descriptive premises.

D.

make certain you are being guided by good intentions and a clear conscience.

### Answers

Hello there.

In constructing a moral argument, the point is to

A.

come to a conclusion that leads to reasonable action consistent with moral values.

A.)In constructing a moral argument, the point is to "come to a conclusion that leads to reasonable action consistent with moral values"

Hope this helps!

A truck makes a sharp turn and a box falls out of the bed, this is best explained using?

### Answers

Newtons third law of motion

The number of electrons in a copper penny is approximately 10*10^23. How large would the force be on an object if it carried this charge and were repelled by an equal charge one meter away? I am using don't panic volume 2. How do you do this problem step by step?

### Answers

Answer:

The force of repulsion between charges will be 2.309 N.

Explanation:

The number of electrons in a copper penny =N =

Charge on an electron =

Total charge of the N electrons = Q

The force be on an object if it carried this charge and were repelled by an equal charge one meter away.

Let the force of repulsion be F.

Distance between the Q and q charges = r =1 m

(Coulomb law)

The force of repulsion between charges will be 2.309 N.

The charge on the electron is 1.6x10^-19C. So, 10^24 of them will be a charge of 1.6x10^5C,F = q1xq2/[(4pi epsilon nought)r^2]

This question is related to inertia: To peel off a piece of paper from a roll, in what way is it better to do it?

a) Slowly pulling the roll

b) Slowly pulling the piece of paper

c) Pulling suddenly the roll

d)Pulling suddenly the piece of paper

### Answers

The way I do it is suddenly, in the same sort of way that magicians try to pull a table cloth off a table when there's things on the table cloth.The sudden approach acts as an impulse of force and starts to accelerate the roll. But, the piece (assuming it has perforations) is off the roll before the roll can move, due to inertia. Then the roll will acclerate, move, slow down and stop. However, in accelerating, the roll will unravel. The bigger the impulse the more it will unravel.+++++++++++++++++++++++++++++++++++++++If on the other hand, the piece of paper is held firmly, and the roll is pulled, then the impulse is presumably given to the paper and the hand whose inertia is a lot more than that of the roll. So, I think I'd actually go for choice c)+++++++++++++++++++++++++++++++++++++This assumes that the roll is free to rotate.I think that a similar idea is behind the design and use of a "ballistic galvanometer". The charge is passed through the galvanometer quickly, as a current pulse. Then the needle starts to deflect, and the deflection is arranged to depend on the total charge that has passed through in the time of the current pulse.

Does a resulting force cause acceleration? true or false?

### Answers

True...A movingobjectwith a zeroresultant forcekeeps moving at the same speed and in the same direction. If theresultant forceacting on anobjectis not zero, a stationaryobjectbegins toacceleratein the same direction as theforce. A movingobjectspeeds up, slows down or changes direction

In an experiment in space, one proton is held fixed and another proton is released from rest a distance of 2.00 mm away What is the initial acceleration of the proton after it is released?

### Answers

I have tried to answer this inverse square Coulomb's law question more fully, but have been blocked from doing so. I do not know why.

The city of Denver is located approximately one mile (1.61 km) above sea level. Assume you are standing on a beach in Los Angeles, California, at sea level; estimate the angle of the resultant vector with respect to the horizontal axis between your location in California and Denver. a) between 1 degrees and 2 degrees

b) between 0.5 degrees and 0.9 degrees

c) between 0.11 degrees and 0.45 degrees

d) between 0.06 degrees and 0.10 degrees

e) less than 0.05 degrees

the power-point says the answer is D, but how do i solve it?

thank you in advance

### Answers

As a thought, I'd say that you need to know how far D and LA are apart in km. If the q doesn't give you that, then it's presumably down to a map, or some other such way of working out their separation distance. Once you've got that distance, and assume that it's a horizontal distance, then you' ve got a right angled triangle. in "normal" trigonometry, it would tan angle = opposite/adjacent. But for small angles, tan angle is approx equal to the angle, I think, as with the sine of a small angle.

An evacuated long tube contains a coin and a feather. If both objects fall together starting from the top of the tube, it is expected that:

### Answers

They will fall together and land together, since there is no air resistance to slow the feather down. Classic experiment, I believe it was tried on the moon years ago.

If you plot the distance d as an ordinate (y-axis) versus the time of fall t as an abscissa (x-axis), do you expect to get a straight line? What type of curve do you expect to get?

### Answers

Since a straight line on a distance time graph implies uniform speed, and falling is an acceleration - a non uniform speed - I woul not expect a straight line.I would expect to get a parabola.This is based on the kinematic equation s=ut+(1/2)at^2.If something is dropped from rest, u = 0; so s = (1/2)at^2Which is, I think, the equation of a parabola.

Answer:

Since a straight line on a distance time graph implies uniform speed, and falling is an acceleration - a non uniform speed - I woul not expect a straight line.I would expect to get a parabola.This is based on the kinematic equation s=ut+(1/2)at^2. If something is dropped from rest, u = 0; so s = (1/2)at^2Which is, I think, the equation of a parabola. is correct give him brainlist

Explanation:

sorry if it seems like i copied im just here to say its correct

A ball is thrown 20.0 m/s at an angle of 40.0° with the horizontal. Assume the ball is thrown at ground level. A. How long does it take the ball to reach the wall?

B. At what height does the ball hit the wall?

C. Is it moving up or down at the instant before it hits the wall?

### Answers

The ball's horizontal component of velocity (ie it's horizontal speed) is 20 cos 40degrees. Without knowing the distance of the ball to the wall it's difficult to go further ...