Recent content by Jstew

It will reflect or refract, depending on the angle. But what does it mean to "reflect completely"?

http://img692.imageshack.us/img692/8996/glassrod.th.jpg I've drawn how the light enters the rod, and I understand how to find theta 2 and theta 3 given theta 1 and the indices of refraction, I just don't know what the problem is asking for.

Homework Statement Consider a solid glass rod of length 75cm and diameter 1.5cm with n=1.46. Light enters the center of the end of the rod from the air. What is the maximum angle of incidence for which the light is totally reflected inside the rod? Homework Equations n1 sin (A1) = n2...

Homework Statement Using a uniform strut, a rigid brace hinged at the floor, a person holds a 30-kg engine in equilibrium while it is being repaired. The strut has a mass of 12.5 kg. A smooth rope passes over a pulley at the end of the strut. (a) What is the force exerted on the rope by...

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Homework Statement A marble of mass m falls through a fluid and is subject to the drag force F=-Av, where v is the velocity of the marble. The marble will reach a terminal speed given by v=(mg)/A. Use dimensional analysis to estimate how long it will take to reach the terminal speed. (Hint...

I figured it out. Set T to Fg and the T and m cancel out, leaving tan(theta)=tan(alpha)

Homework Statement A plum bob suspended from a frame settles to a steady position as the frame slides down a frictionless inclined plane. What is the angle the plumb bob makes with the vertical during the slide? http://img261.imageshack.us/img261/2128/442by1.th.jpg...

So then the pulley is exerting a horizontal force and a vertical force on the rope. (This is the action-reaction I was talking about) If the pulley is exerting force on the rope, how is T=ma and not T=ma+F where F is the force of the pulley on the rope.

To clarify the "action-reaction" comment, what exactly is exerting the force on the pulley and in which direction is this force?

It seems very oddly-worded to me as well. I've copied the drawing as best I could and the wording of the problem verbatim. If the upward force on the pulley is non-zero it seems like it would lead to odd action-reaction pairs: The pulley exerts downward force F on the rope, the cart exerts...

Homework Statement A cart connected to a massless rope has mass 25kg. The rope passes over a fixed pulley (The rope is pulled upwards, the car moves to the right, the pulley is attached to a pole in the ground.) The cart accelerates horizontally at 1.4m/s^2, find the upward force on the...

I was a computer technician for two years in HS, so I'm quite proficient with computers. I'm not comfortable writing code from scratch, but I'm usually able to modify code if I need to change something small-ish. Is this level of proficiency useful, or is it more all-or-nothing with programming?

I'll be a freshman in the fall studying physics, math, and astronomy. A guy from my old HS is a master's degree student at my university, and he hooked me up with a job in an experimental particle physics lab. Basically he said that it's up to me to talk to grad students and professors and...

P=V^2/R, so V^2=R/2 I don't know what to do with these individual maximum voltages.