Maximum velocity of a piston

[Bearbull24.5]

Homework Statement

A piston in an automobile engine is in simple harmonic motion. Its amplitude of oscillation from the equilibrium (centered) position is ±4.73 cm and its mass is 1.733 kg. Find the maximum velocity of the piston when the auto engine is running at the rate of 4380 rev/min.
Answer in units of m/s.

Homework Equations

Vmax=Aw

The Attempt at a Solution

I attempted to take the Amplitude (.0437 m) and multiply it by the angular frequency. I first converted it into revolutions per second and then divided 2pi by the answer I got.

 

[Dadface]

Hello Bearbull,w=2pif.

 

[Bearbull24.5]

And f=1/T and T=4380 rev/min= 73 rev/s?

 

[Bearbull24.5]

Got it wrong again,

Vmax=(.0437m)(2pi(1/73rev/s))

 

[Dadface]

f=4380r/min=4380/60 revs/second=73r/s

 

[MissPenguins]

And f=1/T and T=4380 rev/min= 73 rev/s?

This part is wrong. Remember 1 rev = 2pi.
So you multiply by 2pi, and then 1 min = 60 seconds. So you divide by 60 seconds. I did not get 73 rev/s. I got another number.

 

[Dadface]

w=2pitimes73

 

[Bearbull24.5]

I did 2pi*73 rev/s and then multiplied it by my amplitude (.0437 m). Got it wrong.

 

[Dadface]

I did 2pi*73 rev/s and then multiplied it by my amplitude (.0437 m). Got it wrong.

What answer did you get and what should the answer be?

 

[Bearbull24.5]

What answer did you get and what should the answer be?

I got 20.043989 and I have no idea what the correct answer is supposed to be. I only have one more chance to get it correct

 

[Dadface]

so you carried out the following calculation:
2 times 3.142(pi)times73times 0.0473.I picked up my calculator and did it and got an answer close to yours but not the same.Try again and report back here before you submit your answer.

 

[Bearbull24.5]

Haha. Had the numbers mixed up. Thanks

 

[Dadface]

Haha. Had the numbers mixed up. Thanks

I'm always doing that