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PHYA4: Spring oscillation, max velocity [Help]

I've done this question and I wanted to double check it. Feel free to post if you agree with me. I haven't rounded anything at all, so I think I have the most exact answer. I just need to double-check since I sourced this question from a book which has an error in it. I found this question quite challenging as spring-related questions are my weakest point in Physics.

Here is the question:
A mass of 0.5kg is hung from a spring which extends by 0.06m. The mass is pulled down a further 0.04m and then released. Calculate the maximum velocity of the mass.

Edit: I think it's SHM, I don't know.

Thank you.

My answer (I have not rounded a single thing off - unless my calculator did it by default):

Spoiler

(edited 9 years ago)
Original post by Sayonara
I've done this question and I wanted to double check it. Feel free to post if you agree with me. I haven't rounded anything at all, so I think I have the most exact answer. I just need to double-check since I sourced this question from a book which has an error in it. I found this question quite challenging as spring-related questions are my weakest point in Physics.

Here is the question:
A mass of 0.5kg is hung from a spring which extends by 0.06m. The mass is pulled down a further 0.04m and then released. Calculate the maximum velocity of the mass.

Edit: I think it's SHM, I don't know.

Thank you.

My answer (I have not rounded a single thing off - unless my calculator did it by default):

Spoiler



Yup this is an SHM question.
I'm getting a different answer
Can you post how you got your answer. All the steps...
(edited 9 years ago)
Reply 2
Avatar for Sayonara
Sayonara
OP
11
Original post by FishLover
Yup this is an SHM question.
I'm getting a different answer (1.28 m/s after rounding off to 3 s.f)
Can you post how you got your answer. All the steps...


How did you do it? It looks like you didn't consider all of the energies if your answer is higher.

You must take away the gravitational potential energy gained and consider the elastic potential energy differences? I hope I did mine correctly, but IDK.
Original post by Sayonara
How did you do it? It looks like you didn't consider all of the energies if your answer is higher.

You must take away the gravitational potential energy gained and consider the elastic potential energy differences? I hope I did mine correctly, but IDK.

Sorry I think I plugged in the wrong values :colondollar:. Yup I'm getting the same answer as you. I first found frequency then differentiated the SHM equation and then used that to get the answer...

Is that how you did it?
Reply 4
Avatar for Sayonara
Sayonara
OP
11
Original post by FishLover
Sorry I think I plugged in the wrong values :colondollar:. Yup I'm getting the same answer as you. I first found frequency then differentiated the SHM equation and then used that to get the answer...

Is that how you did it?


Nope, but what equation did you differentiate?

I can't see how you did it by differentiating?

I just considered the energies and used 0.5mv2.
Original post by Sayonara
Nope, but what equation did you differentiate?

I can't see how you did it by differentiating?

I just considered the energies and used 0.5mv2.


I don't really think they would mind either way of getting the answer tbh.

Maybe you aren't given the formula I'm talking about. Mind differ based on exam board..
Anyway, They have given the formula x= A cos (wt)
Then I differentiated that to get v= -Aw sin(wt). Max velocity would be at equilibrium position so we can take sin (wt)=1 so v= -Aw, where w=2 Pi f
I found f using f= 1/2*pi * root(k/m)
I don't really know how to write the maths bits properly here...sorry if it's not very clear..
Reply 6
Avatar for Sayonara
Sayonara
OP
11
Original post by FishLover
I don't really think they would mind either way of getting the answer tbh.

Maybe you aren't given the formula I'm talking about. Mind differ based on exam board..
Anyway, They have given the formula x= A cos (wt)
Then I differentiated that to get v= -Aw sin(wt). Max velocity would be at equilibrium position so we can take sin (wt)=1 so v= -Aw, where w=2 Pi f
I found f using f= 1/2*pi * root(k/m)
I don't really know how to write the maths bits properly here...sorry if it's not very clear..

Thanks, it's perfect. :smile:

I see now.
Original post by Sayonara
Thanks, it's perfect. :smile:

I see now.


Thanks...

Glad I could help :h:

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