Recent content by EkaterinaAvd

logarithm equation and equation without logarithm are eqivalent if [v]=m/s, it doesn't mean that [ln(v)]=m/s of course. They are two different numbers representing the same velocity and can't have the same dimension. but if you are consistent with formulas you have in your calculations, you will...

it depends on units in which v and T are given. you have to extract units from formula Velocity=squareroot Tension/linear density. Units of right and left parts of equation must be the same.

I think that Ek(final)+Ep(final)-Ek(inicial)=-∫Fk dx=-µk ∫(mv^2/R + mgcosø)dx=-µk ∫(mv^2/R + mgcosø)rdø your v under integral depends on theta, it is not a constant over the loop that is why I think you need a differential equation yes, now I see that you choose ø=0 at the bottom and...

I don't think that you want to have t in your system of equations If you use 1) second Newton's law for position with arbitrary angle theta (which you already have) 2) relationship between Fk and N 3) energy-work theorem in differential form (how much kinetic and potential energy change once...

Ok, I see. Calculation would be correct if compession displacement were much smaller then initial height of the block. But 0.653 m and 0.219 m are comparable. So, read post from Gneill.

N= (m v^2)/r + m g cos ø - why did you place gravitational force projection to the right side instead of left? ma = N + mg_r (mg_r - radial component of gravitational force) yes, v during the loop is changing according with the energy-work theorem are you given mu in this problem? You have to...

I'd use a little different approach for this problem: in both initial and final state the spring is at the rest, so 1) consider whether there was any work done by force other than gravitational force and spring elastic force 2) depending on with what you come up in (1), use energy conservation...

part (B) is correct now in N/cm. But if you need answer in SI, you need to transfer it to SI. for part A, you can't expect force and displacement to be equal to each other or not because they have different dimensions. imagine that it had x=5 when y=5 etc. Now let's measure x in meters...

(1) probably just typo, not mx'=-kx but mx''=-kx (2) if you want to go from x = Asin(wt) + Bcos(wt) to x=Ccos(wt+phi), you would have to rewrite the first expression as x = sqrt(AA+BB) (Asin(wt)/sqrt(AA+BB) + Bcos(wt)/sqrt(AA+BB)) ( sqrt(a) is squared root from a) as soon as...

they might mean absolute values of force and displacement and you just should treat it as F=kx. Because negative k would mean that when your spring is stretched, it tends to be streched even more. And when it is contracted, it tends to be contracted even more. (A) Why do you think so? And if it...

you have to express your expression like 1 = A(x-1)^2 + Bx(x-1) + Cx = Dx^2 + Ex + F express D,E,F in terms of A,B and known numbers. and you know that (Dx^2 + Ex + F = 1) for any x. To make it always equal to 1, your coefficients near x^2 and x must be 0 and your free coefficient must be 1.

yes, several of my classmates in grad school came from slightly different majors like Optical Science etc. You might be required to take some undegrad classes during grad program. But to apply to grad program, you will need to pass GRE-Physics which already implies pretty much background. Part...

Hello I am currently doing my PhD studies in US and I am thinking about going back to my home country in the future (probably not right after PhD) And I'm wondering about opportunities to still work in US remotely. (For example, to work several years in some company and then ask them for...

I just like a joke about logicians: Three logicians are sitting in the restaurant. A waitress asks: "Will everyone of you drink coffee?" The 1st logician: "I don't know" The 2nd logician: "I don't know" The 3rd logician: "Yes"

requirements regarding taking subject GRE may differ from school to school. you have to check requirements for particular programs you will apply. also check info about funding because some Departments don't offer funding for master's students