Recent content by will_lansing

sorry i meant 3sin(2t) okay so if you are supposed to square both side of the equation you should get x^2/9=sin^2(2t) how did you get y=4sint(2t)? but if you were to square that you would get y^2/16=sin^2(2t) then if you add the two equations x^2/9=y^2/16 x^2/9-y^2/16=0 is that what...

Homework Statement Give a Cartesian equation for the parametric curve x(t)=3sin(2t) and y=4cos(2t) Homework Equations The Attempt at a Solution I'm not sure if I'm doing this right since x^2+y^2=1 I thought sin^2(2t)+cos^2(2t)=1 should be the right answer am i wrong so...

I still don't see where i went wrong. can you please explain a bit more.

Homework Statement A heat engine operates between a high-temperature reservoir at 690 K and a low-temperature reservoir at 320 K. In one cycle, the engine absorbs 6700 J of heat from the high-temperature reservoir and does 2200 J of work. What is the magnitude of the net change in entropy as a...

no i meant W=P(delta V) I just typed in the wrong thing sorry for the mistake so do you know what i should do

Homework Statement A system expands by 0.75 m^3 at a constant pressure of 125 kPa. Find the heat that flows into or out of the system if its internal energy a. Increases by 65J b. Decreases by 1850 J give answer kJ Homework Equations The Attempt at a Solution P=125 kPA delta...

yeah i got the right answer thanks so much. but i still think that finding limits for sequences are still hard.

so as n approaches infinity cos approaches 0 right so do you just multiply -2.1 by -4.2 to get the answer

okay so if i do it again i get 8.4 lim_{n\rightarrow\infty} \frac{sin\frac{4.2}{n}}{\frac{1}{n}} so in the end i will get 8.4 lim_{n\rightarrow\infty}(-4.2cos(4.2/x)) did i do it right so far so is the answer -35.28 i really don't understand how you are suppose to find the limit can...

Homework Statement Find the limit of the sequence whose terms are given by a_{n}=n^{2}(1-cos\frac{4.2}{n}) Homework Equations The Attempt at a Solution I now that n^{2} goes to infinity so have to use l'hospital rule because you will have infinity*0 which is an indeterminate form...

h=x/2 is what i mean about using the center of mass

solved it. forgot about the center of mass bit.

Ei=mgh Ef=(1/2)mv^2[1+(1/2)mr^2/mr^2] mgh=(1/2)mv^2[1+(1/2)] the mass cancels out gh=(3/4)mv^2 v=\sqrt{(4/3)gh} v=\sqrt{(4/3)(9.81)(.79} v=3.2m/s Is this how you are suppose to do it? I really don't know. Please help

I still don't understand what to do. Are you saying that I should use this formula E_{i}=E_{f} so than mgh+(1/2)mv^2[1+mr^2/mr^2]=0 v=sqrt(gh) but i still get the wrong answer. What should i do? Where did i go wrong?

Homework Statement After doing some exercises on the floor, you are lying on your back with one leg pointing straight up. If you allow your leg to fall freely until it hits the floor, what is the tangential speed of your foot just before it lands? Assume the leg can be treated as a uniform rod...