# Vibrations and waves

#### Dx

I am curious to know that if a mass on a spring undergoes SHM. when the mass is at its MAX displacement from equilibrium, its instantaneous velocity is what?
is it zero!

can someone explain?
Dx

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#### enigma

Staff Emeritus
Gold Member
Well, just before the mass hits the max displacement, the velocity is +deltaV, and just after it is -deltaV. You have to go through zero to get from + to -.

#### Dx

Okay!

I said at MAX displacement that deltav is + or - Max but my teacher says im wrong. It must be less than max but not zero as youve kinda explained, i think
Dx

Right?

#### Tom Mattson

Staff Emeritus
Gold Member
You had it right the first time: The speed at the extrema of position is zero.

If you are moving this way ----->
and then this way <-----

then at some point you had to stop and turn around.

#### Dx

Kool

Hello,

Thanks!
Dx

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