The velocity vector V1 has a magnitude of 5.0 m/s and is directed along the +x-axis. The velocity vector V2 has a magnitude of 4.0 m/s. The sum of the two is V3, so that V3 = V1+V2 Either True or false : The magnitude of V3 can be 9.0 m/s The x-component of V3 can be 5.0 m/s The magnitude of V3 can be -6.0 m/s The magnitude of V3 can be 5.0 m/s The magnitude of V3 can be 10.0 m/s The magnitude of V3 can be 0.0.

Following on Jim Graber's answer to: Can "big rip" rip apart an atomic nucleus?

If the cosmological constant is large enough, even the ground state of a hydrogen atom can be affected. So why is the energy scale for quantum gravity set by the planck mass and not by the cosmological constant? Is it because the cosmological constant can be associated with other theories (inflatons, or vacuum energies of the matter fields, etc.) and thus is just considered an ingredient and not gravity itself? If this does come down to a semantics issue, I'd still be interested to hear if the scale set by the cosmological constant suggests we may be able to see interesting quantum effects at that scale depending on what the cosmological constant 'is'.

A dielectric-filled parallel-plate capacitor has plate area A = 15.0cm2 , plate separation d = 5.00mm and dielectric constant k = 5.00. The capacitor is connected to a battery that creates a constant voltage V = 10.0V . Throughout the problem, use ?0 = 8.85

A jet with mass m = 1.2

the rod below is a uniformly charged semicircle of arc length .14 m. If the total charge on the rod is -7.50 muy c, magnitude and direction of the electric field at point O? Point O is in the center of the semicircle.

The position of a particle moving along the x axis is given in centimeters by x = 9.93 + 1.47 t³, where t is in seconds. Calculate (a) the average velocity during the time interval t = 2.00 s to t = 3.00 s;(b) the instantaneous velocity at t = 2.00 s; (c) the instantaneous velocity at t = 3.00 s; (d) the instantaneous velocity at t = 2.50 s; and (e) the instantaneous velocity when the particle is midway between its positions at t = 2.00 s and t = 3.00 s.

Consider an animal like a horse. Now scale its neck longer and longer.

How can a giraffe, or even worse a huge dinosaur, raise its neck without the tendons snapping? The dinosaur case in particular seems ridiculous. Is there a "physics trick" the animals use to make this more manageable? Or does the tendon tension not scale as badly as my intuitiion is claiming?

In the electron gun of a TV picture tube the electrons (charge ?e, mass m) are accelerated by a voltage V. After leaving the electron gun, the electron beam travels a distance D to the screen; in this region there is a transverse magnetic field of magnitude B and no electric field.

Find the approximate deflection of the beam due to this magnetic field. (Hint: Place the origin at the center of the electron beam

What subject (suggest book titles, etc.) should I study to get a clear grasping of hypersurfaces, 2-surfaces, and integration on them, mostly in special relativity (I'm not messing with general relativity yet).

I was doing some reading on wikipedia and found it interesting that one page says the Grand Canonical Ensemble does not allow for exchange of particles, however another page says it does. So I went on google books and tried to look for a more trust worthy source, again the same happens one source says it allows the other says it doesn't so which is it?

Book that says it does allow exchange: http://www.scribd.com/doc/52426748/46/Grand-Canonical-Ensemble

Another that says it isn't allowed: http://books.google.co.uk/books?id=5sd9SAoRjgQC&pg=PA62&dq=grand+canonical+ensemble+exchange+particles&hl=en&ei=hL6oTZ2THc_p4wbEh-3DCg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CC0Q6AEwAA#v=onepage&q=grand%20canonical%20ensemble%20exchange%20particles&f=false

What gives?

1. explain (include a labeled diagram )kirchhoffs loop rule.

2.explain (include a labeled diagram )kirchhoffs junction rule .

3.using kirchhoffs laws prove the following equation.

R(equ) =R1+R2+R3+.....

Please answer this question using physics formula below:

Why do bearded dragon keep their mouth open in order to regulate their body temperature? We have to use this formula to show how much water they evaporate.

Fomula:

Q= mL

Q/t = mLv/t

Two cars, A and B, travel in a straight line. The distance of A from the starting point is given as a function of time by xA(t)=?t+?t2, with ?=2.60m/s and ?=1.20m/s2. The distance of B from the starting point is xB(t)=?t2??t3, with ?=2.80m/s2 and ?=0.20m/s3.

Part B

At what time(s) are the cars at the same point?

Express your answer numerically. If there is more than one answer, enter each answer separated by a commas.

Part C

At what time(s) is the distance from A to B neither increasing nor decreasing?

Express your answer numerically. If there is more than one answer, enter each answer separated by a comma.

Part D

At what time(s) do A and B have the same acceleration?

Express your answer numerically. If there is more than one answer, enter each answer separated by a comma.

two tiny spheres, A and B, or mass 5g each each carry equal positive charge 2.0uC. They are connected by a .5m long insulating string with negligible mass. only electric forces are relevant in this problem. A) what is the tension in the string B)what is the electric potential energy of the problem c) if the string is cut what is the speed of sphere A when the two are very far apart

A doughnut contains about 280 Calories. (Note: These are "food" Calories.) After eating this doughnut, you decide to compensate by taking the stairs instead of using the elevator. If each stair has a height of 18 cm, how many stairs must you climb to compensate for the doughnut? Assume all the energy in the doughnut can be converted to mechanical energy. (Take 75 kg as the mass of a typical person.)