Simple Harmonic Motion- How Many Times Does the Diaphragm Move Back and Forth?

[ladolce]

Simple Harmonic Motion-Help Please :)

Homework Statement

A loundspeaker diaphragm is producing a sound for 1.5 s by moving back and forth in a simple harmonic motion. The angular frequency of the motion is 8.50 104 rad/s. How many times does the diaphragm move back and forth?

________ times

Homework Equations

ang.freq.=2pi/T

f=1/T

The Attempt at a Solution

Ok, so I plugged in w=85000rad/s and t=1.5s and got T=0.00007392 and f=13528.139 cycles/sec and

multiplied that f i got by 1.5 sec to get 200292.209 cycles which is wrong..

I don't know what i did wrong...can someone help?

 

[nicktacik]

Everything looks right, except f * 1.5s = 20292.209 not 200292.209

 

[ladolce]

thanks! i always make dumb mistakes like that haha..