Velocity  [ENDORSED]


Moderators: Chem_Mod, Chem_Admin

Josh Moy 1H
Posts: 58
Joined: Thu Jul 13, 2017 3:00 am

Velocity

Postby Josh Moy 1H » Wed Oct 11, 2017 10:17 pm

Is Velocity (m/s) the same as speed?

Deap Bhandal L1 S1J
Posts: 77
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 2 times

Re: Velocity

Postby Deap Bhandal L1 S1J » Wed Oct 11, 2017 10:26 pm

In this case it's very similar. Velocity is just speed with direction. Sometimes a negative sign will denote a leftward direction and a positive will denote a rightward direction, but nowhere is this set in stone. As long as the reference point is kept constant throughout the experiment, there should be no problem. But do not get confused with the other v, which stands for frequency.

Chem_Mod
Posts: 18692
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 616 times

Re: Velocity

Postby Chem_Mod » Wed Oct 11, 2017 11:23 pm

Basically, for a physics class no but for Chem 14A yes.
Hope this helps! -Ajith :D

Matt_Fontila_2L_Chem14B
Posts: 39
Joined: Fri Sep 29, 2017 7:07 am

Re: Velocity

Postby Matt_Fontila_2L_Chem14B » Fri Oct 13, 2017 4:44 pm

If we can use them interchangeably for this class, does that mean we can use the speed of light in a vacuum (2.988x10^8 m/s) in De Broglie's Equation?

λ = h/m*v

Would we then just need the mass to determine the wavelength?

Katie Lam 1B
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

Re: Velocity

Postby Katie Lam 1B » Fri Oct 13, 2017 5:31 pm

I went to Dr. Lavelle's office hours today and learned that De Broglie's equation cannot be applied to light or electromagnetic radiation. It can only be applied to particles with rest mass, like electrons, so you can't use the speed of light in De Broglie's equation.

Kathleen Vidanes 1E
Posts: 62
Joined: Fri Sep 29, 2017 7:07 am

Re: Velocity

Postby Kathleen Vidanes 1E » Sun Oct 22, 2017 9:06 pm

After reading this, I am still a bit unsure of how the speed of light relates to velocity. Are they directly related / inversely related? Is speed of light (3.00x10^8m.s-1) interchangeable with velocity?

Bansi Amin 1D
Posts: 51
Joined: Fri Sep 29, 2017 7:05 am
Been upvoted: 1 time

Re: Velocity

Postby Bansi Amin 1D » Sun Oct 22, 2017 9:25 pm

The speed of light can be used as velocity for massless particles like photons. Not too sure about the whole relationship part.

Kyung_Jin_Kim_1H
Posts: 53
Joined: Thu Jul 27, 2017 3:00 am

Re: Velocity

Postby Kyung_Jin_Kim_1H » Sun Oct 22, 2017 10:57 pm

I'm still confused. Can we use the speed of light as our velocity element when the direction part of the vector component is negligible in our calculations?

CalebBurns3L
Posts: 47
Joined: Fri Sep 29, 2017 7:07 am

Re: Velocity  [ENDORSED]

Postby CalebBurns3L » Fri Oct 27, 2017 11:14 am

Yes, the speed of light can be considered a velocity, speed is simply the magnitude of velocity. However, that doesn't mean you can use it has the velocity component in De Broglie's equation. That equation is for particles with mass, not for light waves/photons.

Michelle Lu 1F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am
Been upvoted: 1 time

Re: Velocity

Postby Michelle Lu 1F » Sun Oct 29, 2017 11:10 pm

Speed is basically the absolute value of velocity, because velocity is speed but with direction. They both have the same units m/s.

Sheel Shah 1H
Posts: 33
Joined: Fri Sep 29, 2017 7:04 am

Re: Velocity

Postby Sheel Shah 1H » Tue Nov 07, 2017 10:33 pm

velocity is the absolute value of speed in calculus terms; essentially speed simply analyses magnitude whereas velocity takes into account both magnitude and direction. Velocity is a vector and speed is a scalar. These details are more important in physics and will not play a crucial role in analyzing the speed of an ejected electron using the kinetic energy equation in the photoelectric effect.

Hope that helps! :)

Richard Braun 1I
Posts: 65
Joined: Fri Sep 29, 2017 7:05 am

Re: Velocity

Postby Richard Braun 1I » Sat Nov 11, 2017 7:55 pm

Velocity is speed with a direction.

Kaelie Blanes-Ronda 2L
Posts: 42
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

Re: Velocity

Postby Kaelie Blanes-Ronda 2L » Sun Nov 12, 2017 4:30 pm

Speed and velocity are pretty much equals except that the speed doesn't tell you the direction the person/object is moving in relatively to the starting point x=0. For example a car can be traveling at a speed of 40 miles per hour but that doesn't tell you whether the car is heading west or east. The velocity which is -40 miles per hour would indicate west or +40 miles per hour would indicate east.

Troy Tavangar 1I
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

Re: Velocity

Postby Troy Tavangar 1I » Thu Dec 07, 2017 11:30 pm

Velocity affects direction while speed disregards direction all together. For example, 10 mph west is a velocity while 10 mph is speed.


Return to “Properties of Light”

Who is online

Users browsing this forum: No registered users and 1 guest