Recent content by Tui

Homework Statement 2. A solid copper sphere of radius 15.0 cm carries a charge of 40 nC. Find the electric field (i) 12.0 cm, (ii) 17.0 cm and (iii) 75 cm from the centre of the sphere. (iv) Explain how your answers would change if the sphere were hollow. Homework Equations...

Homework Statement Prove Sech^2(x) = 1 - tanh^2(x) Homework Equations TanH(x) = (e^x - e^-x)/(e^x+e^-x) CosH(x) = (e^x+e^-x)/2 SinH(x) = (e^x - e^-x)/2 The Attempt at a Solution SecH^2(x) = 1/cosh^2(x) =1 / (e^x - e^-x)^2 / 4 =4/(e^x - e^-x)^2 This is where I am stuck. Any...

Any help is GREATLY appreciated D: Kinda urgent

Homework Statement Calculate the angular momentum about the origin O=(0,0,0) of a particle of mass m moving along the following two trajectories: (a) x(t)=vt y(t)=b z(t)=0 (b) x(t)=Rcos(wt) y(t)= Rsin(wt) z(t)=vt Homework Equations L = r x p L = mvr The Attempt at a Solution...

Hey could it be that a(centrefugal or whatever :P) = v^2 / r So I put -9.8 in for acceleration and work out v?

Hey, first of all I'm not looking for the answer I just want a nudge in the right direction :) Homework Statement "a bucket of water is rotated in a vertical circle of radius 1.00m. What is the buckets minimum speed at the top of the circle if no water is to spill out? Homework...

Oh wow I remember the lecturer doing that on the board and wondering what it was. Thanks so much for all your help !

Oh ok cool :) What about part b? Is that just asking for the other equation (Using the opposite point)?

By the way thanks for the help I really appreciate it

Alright looking at a similar question on yahoo answers I think I might be on the right track (?) (2,4,1) - (8,-2,4) = -6i+6j-3k => Equation is: (8,-2,4) + t(-6,6,-3) Am I right or..?

I don't know how to find the vector given 2 points. I know that's probably really stupid of me and it's really obvious :\ I try to pay attentions in the lectures but it's really hard to keep up. So far the only question I've managed to do on the assignment was proving two lines are skewed

I understand vectors but I don't know where to even begin with this question.

Please help, everything is appreciated

150 viewers and no one can help? really? :\

Please help! Parametic vector equation?? My lecturer is incredibly hard to understand and I have NO idea how to do this assignment. If someone could help me with this first question I think I might be able to do the rest by myself: A) Find a parametric vector equation for the line through...