# Search results

1. ### Hydrostatic Force and Pressure

Homework Statement A semicircle with radius 3 m is submerged vertically in water so that the top is 1 m above the surface. Express the hydrostatic force against one side of the plate as an integral and evaluate it I'm not getting the correct answer, so can someone help me to understand my...
2. ### Simple Arc Length Problem

Homework Statement x = 1+3t^2 y=3+2t^3 0<= x <=4 Homework Equations L = integral from a to b of \sqrt{[dx/dt]^2 + [dy/dt]^2} dx The Attempt at a Solution dx/dt = 6t dy/dt = 6t^2 L = integral from 0 to 4 of \sqrt{(6t)^2 +(6t^2)^2} dx = " \sqrt{36t^2 +36t^4} dx = "...
3. ### I think it's a conservation of energy problem

Homework Statement An alpha particle with kinetic energy 10.5 MeV makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude L = p_0 b, where p_0 is the...
4. ### Electric potential on long insulating cylinder

Homework Statement A long, insulating cylindrical shell of radius .06 m carries a linear charge density of 8.5E-6 C spread uniformly over its outer surface. What would a voltmeter read if it were connected between the surface of the cylinder and .04 m above the surface? Homework Equations...
5. ### Work needed to pump water out of spherical tank

Homework Statement A spherical tank is full of water. If radius r = 3m and height h = 1.5m, find the work W required to pump the water out of the spout. (Use 9.8 for g and 3.14 \pi) Homework Equations Work is the integral from a to b of f(x)dx. The Attempt at a Solution Volume= area *...
6. ### Electric Field: not quite getting the correct answer

Homework Statement E1 = 2.9E4 N/C E2 = 8.6E4 N/C Both fields are uniform Homework Equations flux = \int Eperp*dA = Qencl/ \epsilon0 The Attempt at a Solution flux1 = E1cos(30)(.05m)(.06m) flux2=E2cos(30)(.05m)(.06m) (flux1+flux2) = Qencl/ \epsilon0 Homework...
7. ### Gauss's law; large sheet

Homework Statement Two very large, nonconducting plastic sheets, each 10.0 cm thick, carry uniform charge densities \sigma1, \sigma2, \sigma3, & \sigma4 on their surfaces, as shown in the figure . These surface charge densities have the values \sigma1= -6.00E-6 C/m^2, \sigma2=...
8. ### Electric Field magnitude problem help

Homework Statement A very long uniform line of charge has charge per unit length 4.88E-6 C/m and lies along the x-axis. A second long uniform line of charge has charge per unit length -2.44E-6 C/m and is parallel to the x-axis at y1 = 0.408 m. What is the magnitude of the net electric...
9. ### Calculating Flux for Hemispheres of Different Radii

Homework Statement For some reason, I'm not quite understanding this scenario. " Two hemispherical surfaces, 1 and 2, of respective radii r1 and r2, are centered at a point charge and are facing each other so that their edges define an annular ring (surface 3), as shown. The field...
10. ### Stopping the Proton

"Stopping the Proton" Homework Statement An infinitely long line of charge has a linear charge density of 8.00×10−12 C/m. A proton is at distance 14.0 cm from the line and is moving directly toward the line with speed 1500 m/s. I just want a better understanding of this statement: "An...
11. ### Electric Potential Energy

My book first introduces expressions for work and energy by referring to concepts from mechanics and gravitation. It uses the familiar expressions F =mg (-y direction) & U=mgy to explain the expressions it gives for electric potential energy. However... I understand that the force due to gravity...
12. ### Electric field of a charged ring

Homework Statement This is a http://session.masteringphysics.com/problemAsset/1003223/45/14677_a.jpg" [Broken] of the problem -I know that the direction of the electric field at any point on the z-axis is parallel to the z-axis E = k*q/r^2...
13. ### Charge Distribution on a Conducting Shell

This is just a quick conceptual question. If you have a charge on the surface of a conductor, and the gaussian surface within that has a cavity containing a positive charge... and you move that charge off-center, does that affect the charge distribution on the surface of the conductor?
14. ### Basic Gauss's Law problem

Homework Statement We have solid ball of radius rb and charge density \rho. I need to find the magnitude of electric field E(r) at a distance r < rb from the center of the ball and express my answer in terms of \rho, r, rb, and \epsilon 0. Homework Equations Gauss's Law \int EA...
15. ### Understanding Gravitation

I'm putting this here since I'm a high school student who has only completed two years (pre-AP and AP) of introductory physics. If it's misplaced, then I apologize for the inconvenience. So, I've been reviewing for the upcoming AP test, and I just finished re-reading in my textbook the...
16. ### Graphing expressions without given values?

This isn't really a homework problem. I'm studdying for the AP Physics C: mechanics test by working on practice free response problems that my teacher gave me. My question pertains to a problem in the 1993 set of questions. Let's say, for example, a car moves to the right with a constant...
17. ### Static Equilibrium - board problem

Homework Statement A meter stick balances horizontally on a knife-edge at the 50.0 cm mark. With two 5.0 g stacked over the 12.0 cm mark, the stick is found to balance at the 45.5 cm mark. What is the mass of the meter stick? Homework Equations netF = 0 netTorque = 0 The answer is...
18. ### Static Equilibrium Cable Problem

Homework Statement In fig. 13-32, a 50.0 kg uniform square sign, 2.00 m on a side, is hung from a 3.00 m horizantal rod of negligible mass. A cable is attached to the end of the rod and to a point on the wall 4.00 m above the point where the rod is hinged to the wall. (a) What is the...
19. ### Static Equilibrium of an automobile

Homework Statement An automobile with a mass of 1360 kg has 3.05 m between the front and rear axles. Its center of gravity is located 1.78 m behind the front axle. With the automobile on level ground, determine the magnitude of the force from the ground on a) each wheel (assuming equal...
20. ### Finding angular speed of a thin rod.

Homework Statement A thin 1.0-meter-long rod pivoted at one end falls (rotates) from a horizantal position, starting from rest and with no friction. What is the angular speed of the rod when it is vertical? Homework Equations I (of the thin rod) = (1/3)ML^2 The Attempt at a...
21. ### Angular Momentum of a flywheel problem

Homework Statement The angular momentum of a flywheel having a rotational inertia of 0.140 kg m^{2} about its central axis decreases from 3.00 to 0.800 kg m^{2}/s in 1.50 s. a) What is the magnitude of the average torque acting on the flywheel about its central axis during this period? b)...
22. ### Conservation of angular momentum on low-friction bearings

Homework Statement Two disks are mounted on low-friction bearings on the same axle and can be brought together so that they couple and rotate as one unit. a) The first disk, with rotational inertia 3.3 kg m^2 about its central axis, is set spinning at 450 rev/min. The second disk, with...
23. ### Force and Motion w/ Friction

Homework Statement (I'm going to let the coefficient for friction be "u" since the actual greek letter that's generally used doesn't seem to be a a forum option; also, I'm going to use a dash since subscripts aren't an option) A 40 kg slab rests on a frictionless floor. A 10 kg block...
24. ### Armadillo Problem (Newton's Second Law)

Homework Statement For sport, a 12 kg armadillo runs onto a large pond of level, frictionless ice with an initial velocity of 5.0 m/s along the positive direction of an x-axis. Take its initial position on the ice as being the origin. It slips over the ice while being pushed by a wind with a...
25. ### Newton's Second Law Particle Problem

Homework Statement While two forces act on it, a particle is to move at the constant velocity v = (3 m/s)i - (4 m/s)j. One of the forces is F1 = (2N)i + (-6N)j. What is the other force? Homework Equations Fnet = ma The Attempt at a Solution Well, I'm really just wanting a...