# Search results

1. ### Power in an RL Circuit

Okay, I found the formula IE=RI^2+IL(dI/dt) and I used that to solve (b), which turned out to be 19 W, but that formula didn't work when I tried it on (c). I think what I have to do is find the total power in the system and subtract my answer from (b) from that. But I'm not sure. Any suggestions?
2. ### Power in an RL Circuit

An RL circuit in which L = 9.00 H and R = 5.00 is connected to a 24.0 V battery at t = 0. (a) What energy is stored in the inductor when the current is 0.500 A? (b) At what rate is energy being stored in the inductor when I = 1.00 A? (c) What power is being delivered to the circuit by the...
3. ### Inductance RL Circuit

Never mind. I got it.
4. ### Inductance RL Circuit

Okay, so what you said got me thinking, and I remembered that the time constant equals 1/t and that equals L/R so I set 1/1.4 = L/0.3 but that didn't work. Am I on the right track? P.S. is inductance negative?
5. ### Inductance RL Circuit

[SOLVED] Inductance RL Circuit Calculate the inductance in an RL circuit in which R = 0.300 and the current increases to one fourth its final value in 1.40 s. I tried doing this with V=IR, (I know, the easy way didn't work). I also tried I= V/R(1-e^(Rt/L)) but I don't know what V would...

7. ### Square Wire Magnetic field

Also, I know that the direction of the magnetic field is to the left of the page.
8. ### Square Wire Magnetic field

Can anyone help me with this problem? In Figure P22.31, the current in the long, straight wire is I1 = 8.00 A and the wire lies in the plane of the rectangular loop, which carries 10.0 A. The dimensions are c = 0.100 m, a = 0.150 m, and = 0.350 m. Find the magnitude and direction of the net...
9. ### Gauss's Law Sphere Problem

Yes, but the electric field in the cavity isn't zero. That's what initially confused me.
10. ### Gauss's Law Sphere Problem

A sphere of radius 2a is made of nonconducting material that has a uniform volume charge density . (Assume that the material does not affect the electric field.) A spherical cavity of radius a is now removed from the sphere, as shown in Figure P19.62. Show that the electric field within the...
11. ### Oscillating Slingshot

Also, the problem defines L as the horizontal aspect of the triangle. Can I use the small angle theorum to assume that the hypotenuse is the same as the horizontal component?
12. ### Oscillating Slingshot

I know that max acceleration equals Aw^2 and we've used the formula a=Aw^2 cos(wt+phi)
13. ### Oscillating Slingshot

I've never seen that kind of equation before, except in the equation A=[F/m]/(sqrt(w2 - (k/m)2) , which turns into something kinda similar when you solve for w. Also, what is the "d" in md^y/dt^2 = -2Ty/L?
14. ### Oscillating Slingshot

A ball of mass m is connected to two rubber bands of length, L, each under tension T, as in Figure P12.49. The ball is displaced by a small distance y perpendicular to the length of the rubber bands. (a) Assuming that the tension does not change, show that the restoring force is -2yT/L ...
15. ### Dampened Oscillations Problem

Never mind. It turns out I was using the wrong formula.
16. ### Dampened Oscillations Problem

[SOLVED] Dampened Oscillations Problem A pendulum of length 1.00 m is released from an initial angle of 15.0°. After 1200 s, its amplitude is reduced by friction to 5.5°. What is the value of b/2m? How do you do this one? I know it has something to do with the formula w= sqrt(W0^2 -...
17. ### Pendulum Oscillations Problem

Never mind. I figured it out. Just put I into T=2(pi) sqrt(I/mgd) and the mass cancels out.
18. ### Pendulum Oscillations Problem

It definitely doesn't give the mass, although I know you need it to find MOI. Does anyone know a way around this?
19. ### Pendulum Oscillations Problem

[SOLVED] Pendulum Oscillations Problem A very light rigid rod with a length of 0.500 m extends straight out from one end of a meter stick. The stick is suspended from a pivot at the far end of the rod and is set into oscillation. (a) Determine the period of oscillation. (Hint: Use the...
20. ### Potential energy of an Atom

Ue = (9.0e9) (1.6e-19)(-1.6e-19) / (5.29e-11)
21. ### Potential energy of an Atom

How do you find the electric potential energy of a hydrogen atom using the Bohr model? I tried doing U<sub>E</sub> = K(q1)(q2)/r, using the charge of an electron and the charge of a proton for q1 and q2 and using the Bohr radius for r, but that didn't work. How do you do this? (P.S. the answer...
22. ### Net Gravitational Force Problem

I got the second problem so thanks for that, but the first one is still giving me trouble. I set the two equations equal to each other. The 60 kg and G both canceled out so when I cross multiplied I got 700kg(r2)^2 = 200kg(r1)^2. Then I used the equation r2=0.7 m -r1 and substituted that in for...
23. ### Net Gravitational Force Problem

Problem 1: I tried setting them equal, but then you get (G*700*60)/r^2 = (G*200*60)/r^2. You can't solve for r since they cancel each other out. Am I doing something wrong? Problem 2: How do you solve for field strength? Is it just the force divided by the mass? If 9.8 m/s^2 equals 9.8...
24. ### Net Gravitational Force Problem

I have two problems: can anyone help? First Problem: A 200 kg object and a 700 kg object are separated by 0.700 m. (a) Find the net gravitational force exerted by these objects on a 60.00 kg object placed midway between them. (b) At what position (other than an infinitely remote one) can...
25. ### Physics help: rotational mechanics satellite

Okay, I found my mistake. I just made an error adding the moments of inertia. Thanks for your help.
26. ### Physics help: rotational mechanics satellite

Okay, first I figured out the initial rotational velocity by using a=R(omega)^2, using 90m for R and 9.8 m/s^2 for a. Then I figured out the total initial moment of inertia by doing I + 150(M)(R)^2 I used those to figure out the angular momentum by doing L=(I)(omega), using the I and omega I...
27. ### Physics help: rotational mechanics satellite

Homework Statement A space station shaped like a giant wheel has a radius of 90 m and a moment of inertia of 4.50 108 kg·m2. A crew of 150 are living on the rim, and the station's rotation causes the crew to experience an acceleration of 1g (Fig. P10.47). When 100 people move to the center of...