Ask Me Help Desk - Frequency and amplitude of motion and acceleration

Close: I get 112 rad/s

is it definitely 112 I get 115.4

square root of 0.16 squared - 0.08 squared then dived all that by 16 = 115.4

Quote:

Originally Posted by bayley86

is it definetly 112 i get 115.4

square root of 0.16 squared - 0.08 squared then dived all that by 16 = 115.4

I don't understand what formula you are trying to write out. Do you mean this:

$ \frac {\sqrt { (0.16m)^2 - (0.08m)^2}} {16 m/s} \ ? $

Note that the units of this formula would work out to be seconds, but you need an answer in radians/second. So once again - watch your units!

Using the formula I gave you in my previous post:

$ 16 \frac m s = \omega \sqrt{x_o^2 - (0.08m)^2} $

You know that $x_o = 0.164 m$ . So rearrange to get:

$ \omega = \frac {16 \frac m s}{\sqrt{(0.164m)^2 - (0.08m)^2}} = 111.8 s^{-1} $

so the frequency = 17.79Hz I tried to figer out the acceleration to I get 1499.9 meters per second squared

Quote:

Originally Posted by bayley86

so the frequency = 17.79Hz

Good!

Quote:

Originally Posted by bayley86

i tried to figer out the acceleration to i get 1499.9 meters per second squared

Right - except the exact answer is actually -1500 m/s^2. Note the minus sign, because for positive displacement the piston has a negative acceleration.