Maths / physics question HELP

[Synchromesh]

Is the last step correct?

The formula for radioactive activity is;

If A = A(0) e ^ - lamba t

Therefore

A/A(0) = e ^ - lamba t

Therefore

ln A/A(0) = lamba t

[Use Psychology]

- lambda t?

[Another Fluffer]

I think it's - lambda t.

Good luck to us both SM!

[Synchromesh]

Hmm. For some reason in my notes I have it down without the minus. Does anyone else know?

[TheVole]

I think you have to take natural logs (ln) of both sides to get rid of the e and stop the -lambda t being a power.

I'm assuming AQA physics, Monday morning?

Edited by TheVole on Saturday 16th June 15:45

[Another Fluffer]

TheVole said:

I'm assuming AQA physics, Monday morning?

[TheVole]

Another Fluffer said:

TheVole said:

I'm assuming AQA physics, Monday morning?

Snap!

[McSam]

Minus lambda t, with certainty.

You can't just chuck signs away, my boy

[David87]

Hmm. I only did one day of A-level physics; now I remember why. Good luck, guys!

[Vilhelm]

I've got it too.

I'm a bit useless when it comes to physics.

[Another Fluffer]

Vilhelm said:

I've got it too.

I'm a bit useless when it comes to physics.

That makes 4 of us (that I'm aware of)

Don't worry, so am I!

[Synchromesh]

Another Fluffer said:

That makes 4 of us (that I'm aware of)

Don't worry, so am I!

And evidently we're all hard at work revising...

Oh, and I'm useless at it too. Wish I'd never chosen it but that's another story for another day.

[Another Fluffer]

Clearly!

Story of my life.

[llewop]

Synchromesh said:

Is the last step correct?

The formula for radioactive activitydecay is;

If A = A(0) e ^ - lamba t

Therefore

A/A(0) = e ^ - lamba t

Therefore

ln A/A(0) = lamba t

fixed that for you

sorry - you get picky about things being right, especially as there are so many examples of messed up fomulae, units, definitions etc

[Synchromesh]

llewop said:

Synchromesh said:

Is the last step correct?

The formula for radioactive activitydecay is;

If A = A(0) e ^ - lamba t

Therefore

A/A(0) = e ^ - lamba t

Therefore

ln A/A(0) = - lamba t

fixed that for you

sorry - you get picky about things being right, especially as there are so many examples of messed up fomulae, units, definitions etc

Ok. Except with the minus on the last formula right?

[Vilhelm]

Synchromesh said:

Another Fluffer said:

That makes 4 of us (that I'm aware of)

Don't worry, so am I!

And evidently we're all hard at work revising...

Oh, and I'm useless at it too. Wish I'd never chosen it but that's another story for another day.

I'm hard at work revising, I'll have you know. I just stared at a textbook for an hour. That's today's graft done.

[McSam]

Synchromesh said:

Ok. Except with the minus on the last formula right?

Yes, ffs

[spikeyhead]

Of course there's a minus there, otherwise it wouldn't be decaying with time.

If you're not sure on a formula, do a quick plot of it in Excel and see the shape to see if it makes sense

[Another Fluffer]

Vilhelm said:

I'm hard at work revising, I'll have you know. I just stared at a textbook for an hour. That's today's graft done.

My exact work ethic!

[Synchromesh]

Another Fluffer said:

Vilhelm said:

I'm hard at work revising, I'll have you know. I just stared at a textbook for an hour. That's today's graft done.

My exact work ethic!

Ok, the dreaded question, how did it go for you guys?