What Steps Are Needed to Determine the Mass in a Spring Oscillation Problem?

[JeremyStudent]

1. A block of unknown mass is attached to a spring with a spring constant of 6.5 N/m and undergoes simple harmonic motion with an amplitude of 10 cm. when the block is halfway between its equilibrium position and the end point, its speed is measured to be 30 cm/s. Find the mass of the block, the period of motion, and the maximum acceleration of the block/b]

Me and my friend have been stuck on this problem for a while now, we went into thinking it was going to be easy, only to find ourselves rather stumped, we tried using energy to solve an equation with mass in it, but absolutely failed, if anyone could point us in the right direction it would be much appreciated.

 

[Doc Al]

What did you try? Call the mass "m" and consider the total energy when at the point in question.

 

[JeremyStudent]

I don't know how to write the equations the way I see on other posts, so you'll have to bear with me.

Basically, we solved the energy using 1/2kA^2 then set an energy equation with m in it equal to our result. however as soon as we set it up, we saw that it made no sense since the m's would cancel out (m * k/m). After that we tried applying what we knew about the graphs (velocity, position), but that didn't get us anywhere either.

 

[Doc Al]

I don't know how to write the equations the way I see on other posts, so you'll have to bear with me.

Don't worry about using the fancy equation format, just type them in.

Basically, we solved the energy using 1/2kA^2 then set an energy equation with m in it equal to our result.

Sounds good to me.

however as soon as we set it up, we saw that it made no sense since the m's would cancel out (m * k/m).

Show exactly what you did.