## Velocity

$\lambda=\frac{h}{p}$

405289292
Posts: 52
Joined: Thu Oct 03, 2019 12:16 am

### Velocity

If we calculate a velocity for an electron, proton or neutron that is higher than the speed of light, should we assume we did something wrong, or is there possibility for this to be an answer and we have to say that this is "unreasonable?"

Khushboo_3D
Posts: 60
Joined: Wed Sep 18, 2019 12:19 am

### Re: Velocity

In this case, I guess such an answer would be unreasonable or not possible because there is nothing that can have a speed greater than that of light.

Abigail Sanders 1E
Posts: 91
Joined: Wed Sep 11, 2019 12:16 am

### Re: Velocity

I agree, since nothing can have a velocity higher than the speed of light I would assume that something in the calculation would be incorrect. Maybe retry the problem or message if you still have questions about a specific example.

805394719
Posts: 88
Joined: Wed Sep 11, 2019 12:16 am

### Re: Velocity

As far as we know, nothing can be faster than light, so if the speed of an electron, proton, or a neutron is faster than speed of light, there must have been an error in the calculations. The reason for nothing being greater than the speed of light is due to the absolute space-time in physics which states that objects move not in space but absolute space-time which leads us to the conclusion that passing the speed of light is impossible since you are moving in something where your movement through space and time will add up to the speed of light.

Maya Beal Dis 1D
Posts: 87
Joined: Sat Aug 17, 2019 12:16 am
Been upvoted: 2 times

### Re: Velocity

In problem 1B.21 you must know the conversion between miles per hour and meters per second. Are these conversion factors something we must memorize or will test problems always be given in SI units?

Cynthia Gong 1L
Posts: 51
Joined: Fri Aug 09, 2019 12:15 am

### Re: Velocity

For tests I believe everything will be in SI units. If not, we will get the conversion factors

PriscillaLi_3G
Posts: 63
Joined: Fri Sep 27, 2019 12:30 am

### Re: Velocity

You should assume that a velocity > 3x10^8 is unreasonable

KBELTRAMI_1E
Posts: 90
Joined: Sat Jul 20, 2019 12:17 am

### Re: Velocity

405289292 wrote:If we calculate a velocity for an electron, proton or neutron that is higher than the speed of light, should we assume we did something wrong, or is there possibility for this to be an answer and we have to say that this is "unreasonable?"

I think we did an example problem like this, I don't know if an "unreasonable" answer will ever come up on an exam, and if that's the answer you get, there's no harm in double checking. I haven't come across any like that in the homework.

Diana_Diep2I
Posts: 108
Joined: Sat Aug 17, 2019 12:17 am

### Re: Velocity

You should double check when you have an unreasonable velocity. But like we did in the example problem, it could indicate that the atom's size was too small because the entire point of that problem was to show that there was a limit to how small an atom could be. Usually, atoms have a diameter of 10^-10.

Luyan Zhang - 2D
Posts: 88
Joined: Sat Jul 20, 2019 12:16 am

### Re: Velocity

Yes, this answer is unreasonable, and you should definitely recheck your work. Perhaps you've made a calculator error.

PriscillaLi_3G
Posts: 63
Joined: Fri Sep 27, 2019 12:30 am

### Re: Velocity

It would be considered unreasonable.

Nyari Muchaka_Discussion 4A
Posts: 53
Joined: Thu Sep 19, 2019 12:17 am

### Re: Velocity

If this is based on the Heisenberg Indeterminacy Equation then if the velocity is larger than the speed of light you must assume you have been given an incorrect atomic model which goes to prove that the mass of an atom has to be a certain size or larger in order to properly abide by the laws of the universe aka nothing can be faster than the speed of light. Since wavelength=h/mv, the mass has to be large enough for the wavelength to not be larger than the speed of light.

Sofia Q
Posts: 49
Joined: Sat Aug 17, 2019 12:15 am

### Re: Velocity

It would be considered unreasonable.

Kyle Thorin
Posts: 50
Joined: Sat Aug 24, 2019 12:16 am

### Re: Velocity

This is unreasonable because the fastest thing we know is light.