Recent content by Noir

Cheers, the second methord worked a treat! I'll look into the lagrange stuff, looks interesting :) Thanks once again.

Homework Statement A window of fixed perimeter is in the shape of a rectangle surmounted by a semi-circle. Prove that its area is greatest when its breadth equals its greatest height. Homework Equations SA = lw + (pi*l^2)/4 <--- Thats what I got the surface area to be. Perimeter = 2w +...

Thanks for your reply, but I'm still unclear on how the reverse voltage, or stopping voltage relates to the equarion.

Homework Statement When 520nm light falls on a metal, the current through the circuit is brought to zero by a reverse voltage of 1.13V. What is the threshold frequency for this metal. Homework Equations E = h.f The Attempt at a Solution Using the above formula I get an threshold...

Homework Statement A toy rocket is projected vertically upwards from rest and it rises with an acceleration of (9-5t)g m / s^2 for the first two seconds and, thereafter, freely against gravity. Find: the maximum speed and the maximum height. Homework Equations a = (9-5t)g for the first 2...

Homework Statement An ellipse is rotated around the y-axis, find the volume of this solid. Homework Equations x^2 / a^2 + y^2 / b^2 = 1 \pi\int_{a}^-a x^2 dy The Attempt at a Solution I'm having trouble solving this; I know that the upper and lower bounds of the curve occur on...

It means that at 3 seconds the displacement of the body is 0 m from the starting point. This doesn't help me find distance.

Distance and Displacement are different. If I sub in 3 for t in the displacement equation I get 0. Can you explain what you said with an equation?

"Distance is the scalar value of how far an object has traveled regardless of direction. Displacement is the vector value of how far an object has been displaced, meaning how far is it from where it started. "

It gives -3 when the answer is 13m.

I integrated the velocity function and found a displacement equation; d(t) = t^3 - 2t^2 -4t + 3. Except this gives displacement, not distance. Thats why I'm stuck :(

Homework Statement the velocity v m/s of a body moving in a straight line is given by v = 3t^2 - 4t - 4. if the body has an initial displacement of 3 m from O, find: *a. the displacement and acceleration at any time t s; *b. the time when the body is momentarily at rest; *c. the distance...

Thanks for the reply dx, sorry for my late response. Thanks for helping me but I have a quick question, how do you get the 1/x + 1/y = 1 relationship - It sounds stupid, and I know it works , but I seem to be missing a step in my head.

Homework Statement Apparantley the following problem can't be solved with a graphics calculator and we have to state why this is, and give all the possible solutions. A ladder AB leans against the side of a building. Where the wall meets the ground is a cubic packing case 1m x 1m x 1m. The...

Sorry for any confusion. Much like this equation right here; z^4 + 3iz^3 - (4 + i)z^2 - 3iz + 3 + i = 0 I think your right; I was just lucky my dodgy maths worked! I don't see how replacing i with -1 would, or even could work now...