Recent content by Ki-nana18

I just realized I posted this in the wrong section of the forum. Sorry.

Here is the problem verbatim: The polar and azimuthal angles of a vector are Θ1 and Φ1. The polar and azimuthal angles of a second vector are Θ2 and Φ2. Show that the angle ϒ between the two vectors satisfies the relation: cos ϒ = cosΘ1*cos Θ2+sinΘ1*sinΘ2*cos(Φ1-Φ2) Hint: write out the...

Homework Statement A Carnot heat engine operates between temperatures T1= 400K and T2= 300K. In each cycle the engine receives Qin=1200 J from the high temperature reservoir. a) Calculate the heat Qout delivered to the low temperature reservoir. b) Suppose the engine is operated in reverse as a...

Homework Statement If a block slides w/o friction down a fixed, inclined plane with an angle theta of 30 degrees, what is the block's acceleration? (This problem is an example from my textbook, meaning the solution is available. I am confused on the method that they used. Any clarification...

To find the enthalpy of formation and entropy of formation its the summation of products minus the summation of the reactants, each multiplied by their respective coefficients. Double check your entropy calculation.

So multiplying by kg of Au was right?

Homework Statement The following data were obtained for trace elemental zinc in a particular sample of high purity (%Au> 99.99%). The results are given in mg Zn/ kg Au. 15.38, 15.17, 15.33, 14.88, 14.71, 15.42, 15.60, 15.22 Find the zinc content and the uncertainty at 95% confidence...

Homework Statement The problem statement is attached. Homework Equations The Attempt at a Solution How do I start this problem?

May I have some help on this?

Homework Statement Use cylindrical coordinates to find (a) the volume and (b) the centroid of the solid S bounded above by the plane z=y and below by the paraboloid z=x2+y2. Homework Equations V= ∫∫∫dv x= r cos θ, y=sin θ, z=z The Attempt at a Solution For the first integral I got...

How fast the function increases?

Sorry. \nablaf=<2x, 4 cos(4y)>. Does the gradient at P0 tell me the direction in which the function increases most rapidly?

Okay, I found the gradient <2x+sin(4y), x^2+4cos(4y)> and at point P0 it is <2,5>. Now if I only have one point how do I find the unit vector wouldn't I need another point or an initial vector?

Homework Statement Find the direction in which the function f(x,y)=x^2+sin(4y) increses most rapidly at the point P0=(1,0). Then find the derivative of f in this direction. Homework Equations The Attempt at a Solution I think I have to find the gradient at point P0 and then find...

Thank you so much! :smile: