Recent content by Shaye

I have only be able to write something like: 2x(2π√(l/g)) = 2π√(m/k) 2π is a constant therefore; 2x(√(l/g)) = √(m/k) You could square both sides; 2^2x(l/g) = (m/k) But now I'm lost as to how to proceed. PS- Book answer is B Thanks

Yeah I should probably start to do this going forward @PeroK Good tip!

Thanks @Steve4Physics

The book gives an answer of Q = 3.2 x 10^-19C I get an answer of 6.67 x 10^-19C. Workings below:

Thanks @Orodruin and @haruspex. After much hand holding I eventually got it now lol

The only thing I can think of is p=m/v and m=pv and ke = 1/2(pv)*v^2...but I'm still at a loss

The marker wrote that the answer is 4 and it's because m and v double. I don't understand how m doubles??

Thanks everyone! A DOH! moment for me. Keeping track of the vectors is very useful

Maybe a silly question but on the above question using the conservation of momentum: momentum before firing (0) = momentum after firing (55*35)+(M*2.5) If I re-range the above it's M = -(55*35)/2.5 = -770kg. I can I reconcile that minus sign (basically get rid of it)? Thanks

I mean what I found similar was the fact that you could take moments about any point on the ruler example e.g. at [0.2,0.8], [0.4.0.6] etc. and when you add the moments up they should always equal the couple...

The books solution says to take moments about x2 to find the force of x1 as 110N to 2 significant figures. Then by equilibrium: X1 + X2 = 250N therefore x2 = 250N - 110N = 140N. I understood this to be (4/9)*250 = 110 2 s.f. Similar to the reasoning of a couple i.e. (Couple = F*d) for...

Thanks Delta2. Sorry I got confused. I didn't think about the CoM/CoG where all the weight is acting. But now it's fine :-) The sum of the moments about the CoM should total 250N

Moment about X2 to calculate force at X1: x1 * 9 = (250 * 2) Therefore, x1 = 500/9 = 55.5N The book however gives force at x1 as 110N. So I figured I have not understood a concept somewhere

Phew! Thanks. I thought I was going mad

Advance Physics for You https://www.amazon.com/dp/1408527375/?tag=pfamazon01-20