Recent content by EzequielSeattle

The power radiated from Pluto's surface is equal to half of the total power it receives from the Sun, because the albedo is 0.5. Right?

You can get the necessary angles from the given distances. To find the angle θ in the picture, it is arctan(x2/(D/h)). Do you see why?

Hey all, I think that I'm doing this problem correctly but I'm getting an answer that's a couple thousand Kelvins off. Sorry if I should have posted this in the "advanced" section. 1. Homework Statement Part of a flat region of Pluto has the Sun directly overhead. Its surface temperature is 58...

Thank you! I was accidentally using γ=5/7 instead of 7/5. It works now.

Homework Statement A pocket of air rises 1000 meters. Estimate how much it cools. Use the atmospheric law to determine pressure at 1000 meters. Homework Equations P = P0 * e-Mgz/RT PVγ = constant TVγ-1 = constant The Attempt at a Solution Using the atmospheric law, I found the pressure at...

Would dV/dt just be the derivative of the right side of my equation above? That is, dV/dt = -(V0/RC)*e-t/RC? Then, since I = C*dV/dt, I = -3 volts/10 ohms * e(10 s)/((10 ohms)*C) I feel like that doesn't help, because then I just have another unknown (I).

So I can arbitrarily say that Vc(10 s) is, say, 1.5 volts? And then solve for C, which would give 1.4 farads. Isn't that considered a really really high capacitance?

Homework Statement Imagine that you have a light-bulb that has a resistance of about 10 ohms and that can tolerate a maximum voltage of 3 volts. Imagine that you want to connect this to a charged capacitor large enough to keep the bulb glowing reasonably brightly for more than 10 seconds...

a(mr2 I) = -mgr2 a = -(mgr2)/(mr2+I) Thank you, that's correct. I could cry tears of joy.

Homework Statement I have two equations. The first is for all of the forces on a hanging mass from a pulley. The second is for the sum of the torques about the pulley from which the mass hangs. I simply have to combine the equations to find the acceleration of the object. I have attempted every...

Homework Statement So this is a small part of a much larger problem that I'm working on that I don't want to post here. Basically, I want to find the contribution to the torque about the hinge of a ladder BY the mass of the ladder itself. A ladder is propped open at an angle α. What is the...

Ok, yeah, I realize that that's not the equation and it ought to be α. I decided to try a different approach. The torque on the pulley is equal to rg(m_2 - m_1). The torque is also equal to Iα, or I(a/r) Combining my two equations for the torque, I get rg(m_2 - m_1) = (2/3)(m_pulley)r^2 *...

OK, I've tried this and here's what I've got (T_2 is the tension in the string connecting m_2, T_1 is the tension in the string connecting m_1) τ=T_2 * r - T_1 * r a = αr a will be the same as the acceleration of mass 2, because mass 2 is on a string connected to the pulley. Iω = τ ω = τ/I...

Homework Statement Two blocks, of masses m1 and m2 (with m1<m2) are attached by a massless string of fixed length that runs over a pulley which is free to rotate about its fixed center. The pulley has mass m3, radius r3, and rotational moment of inertia I = (2/3) m3 r3^2 about its center (it...

Just because I think this is intrinsically related: a hand pulls a block connected to a spring away from a wall to which the other end of the spring is attached. The initial and final velocity of the ball is zero. Kinetic energy doesn't change as a result. Is the work then zero? I feel like I'm...