physics homework

1. Solving symbolically

1. Homework Statement You are climbing in the High Sierra when you suddenly find yourself at the edge of a fogshrouded cliff. To find the height of this cliff, you drop a rock from the top; a time T later you hear the sound of the rock hitting the ground at the foot of the cliff. a. If you...
2. How to get better at theoretical homework problems

I’m having lots of trouble in my honors physics class with the theoretical homework problems that are assigned. The entire concept of learning to solve things theoretically, and then applying it is brand new to me. I’m decent at figuring out the applied problems, but pure theory stumps me. I...
3. Electric Fields and Electric forces help

1. Homework Statement This is the question Structure opposite comprises 5 ions each of which has lost one electron. The sides of the square formed by the 4 outer ions are of length 0.2nm Ion E is at the midpoint 1.What is the force on A due to ion A? 2. Homework Equations I'd imagine: F=...
4. Using a CCD camera to solve physics problems

(Sorry for Length) 1. Homework Statement You have decided to use a CCD camera to check if a 16th magnitude quasar is variable. You can presume that all of the light of your quasar falls on one pixel. You know that a star with a magnitude of 0 would deliver 1 × 10^9 photons/second to one pixel...
5. B Help on Circular motion

<Moderator's note: Removed template prior to moving it from Homework.> I am looking at centripetal acceleration, and I know that even at a constant speed the object is acceleration because its velocity is changing. But I don't understand how it is changing, like when is it negative and when is...
6. Refraction Problem

1. The problem statement, all variables, and given/known data A scuba diver is underwater. She looks up and sees a bird flying in the sky. Compared to its actual distance, the bird appears to be.... 1. Closer 2. At actual distance 3. Further 2. Homework Equations n1sin(θ1)=n2sin(θ2) 3. The...
7. How did they get this answer?

This is a worked problem, so they're just basically giving examples on how you would solve this type of problem. My issue is... how did they get 2.86s? Please someone help this has been driving me crazy.
8. Open Tube Resonance

1. Homework Statement A long tube that is open at both ends is used to construct a musical instrument. The sound waves that enter the tube are generated by a taut wire with a tension of 600 N and a linear mass density of 0.031 kg/m. If the length of the tube is 2.4 m and a hole is cut in the...
9. Friction of rubber box on concrete floor

1. Homework Statement A 10 kg rubber box is resting on a concrete floor. A force of 200 N is then applied to this box in a horizontal direction. What is the magnitude of the friction force on the box? 2. Homework Equations This is a question about applying newton's laws so Fsmax = μs η and η...
10. Arrow Loses Mechanical Energy

1. Homework Statement A 125 - G arrow is shot vertically upwards with a Vi of 28/ms. Assuming a 20% loss in Mechanical Energy while ascending, what maximum height above the position it was shot does it reach? 2. Homework Equations Vi= 28m/s Vf= O m/s D= ? a= -9.8 m/s Vf^2= Vi^2 + 2aD Eg =...
11. Energy Change Equation

1. Homework Statement A person performs 6.1 J of work to lift an object without acceleration to a particular height on Earth. Write an equation describing that energy change and analyze it to determine how different the energy would be required to lift the same object to the same height on the...
12. Electric Fields (Uniformly Charged Plates)

1. Homework Statement In the figure two large, thin metal plates are parallel and close to each other. On their inner faces, the plates have excess surface charge densities of opposite signs and magnitude 7.76 × 10-22 C/m2. What is the magnitude of the electric field at points (a) to the left...
13. Basic Forces Question from 9th grader - Hard to put in words

1. Homework Statement I have here a problem asking me to find the tension force on the lower end of a rod with mass of 0.6 kg. The rod connects two blocks, the first / upper one has a mass of 5.0 kg while other/lower one has a mass of 4.0 kg. There is an upward force of 150 N applied on the...
14. Newtonian Mechanics/Forces Question

These buckets are being suspended. The cords have no mass and each bucket is 3.5 kg. a.) Find the tension in the upper cord (T1) and the lower cord (T2) b.) If the apparatus is pulled upwards from the top of the upper cord, what are the new tensions of each cord? I understand the...
15. How to Calculate change in volume produced by a piston?

1. Homework Statement Hello all! I need a little bit of help with my physics homework! It asks me to calculate the change in volume produced by the piston, and it gives me the equation: ∆V= Ax∆d 2. Homework Equations 3. The Attempt at a Solution Now I know that A= 1x 10-^16m^2 And...
16. Resolving forces in equilibrium on inclined plane

1. Homework Statement Solve for the forces P and N acting on an object in equilibrium on an inclined plane. Weight=10N, angle is 30 degrees http://blob:https%3A//www.physicsforums.com/d431a152-5681-411b-ba57-809320539165 2. Homework Equations Trigonometry, i.e. sin, cos, tan rules. The 'Z'...
17. Could Someone Look Over My Work? (particle accelerator design problem)

1. Homework Statement You want to construct a simple particle accelerator and hit on the following design: you will take two oppositely charged plates with small holes drilled into them and set them up parallel to each other. You will create a vacuum between the two plates and fire a beam of...
18. Applying Relative Motion to One Dimensional Motion Equations

<<Moderator note: LaTeX corrected>> Problem: > Two cars A and B move with velocity $60 kmh^{-1}$ and $70 kmh^{-1}$. After a certain time, the two cars are 2.5 km apart. At that time, car B starts decelerating at the rate 20 kmh-2. How long does Car A take to catch up with Car B? I tried to...
19. [ansys] simulation of permanent magnet in 3D

1. Homework Statement The problem is to model a permanent magnet with a torus core .I just wanted to know how to attach attribute of magnet to a volume in ansys 15.0. I solved the problem in 2D but in 3D the results are not satisfactory and I'm not able to point out the mistake by me. the...
20. Period of limit cycle?

1. Homework Statement I'm given this system: \dot x = Ax^2 y + 1 - (B+1)x \dot y = Bx - Ax^2 y (a) Find the value of B when hopf bifurcation occurs. (b) Estimate the period of the limit cycle in terms of $A$ and $B$. 2. Homework Equations 3. The Attempt at a Solution I have found...
21. Torque Required to bring a drum to rest

1. Homework Statement I have a problem involving a goods lift with a cage m1 = 1500kg which is raised at V = 4m/s via a winding drum with a radius of 0.6m with the help of a counter weight of m = 900kg. i am asked to find the braking torque required to bring it to rest in 1 1/3 seconds. Also i...
22. Uniform Circular Motion question

1. The problem The answer is A. 2. Homework Equations x = Acoswt y = Asinwt 3. The Attempt at a Solution C is not correct because the x & y positions are in terms of sin & cos, so the acceleration can't be constant. D is not correct because x & y are oscillating in value. E is not correct...
23. Escape velocity problem

1. Problem A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is a) 2 v b) (√2)v c) v d) v/2 e)...
24. Convex Lens and Magnification

1. Homework Statement You wish to obtain a magnification of -2 from a convex lens of focal length f. The only possible solution is to: A) place a virtual object at a distance 2f/3 from the lens. B) place a virtual object at a distance 5f/3 from the lens. C) place a real object at a distance...
25. Circular Motion and Gravitation of tether ball

1. Homework Statement There is a tether ball swinging around in a uniform circle on a rope that is 1.90m long. Marcus hit the ball so hard that the string holding the ball made a 20.0 degree angle to the horizontal. What is the tension in the rope if the ball has a mass of 1.40 kg? Assume that...
26. Altitude of Satellites above the Surface of the Earth

1. Homework Statement A) Suppose you are on Earth's equator and observe a satellite passing directly overhead and moving from west to east in the sky. Exactly 12.0 hours later, you again observe this satellite to be directly overhead. How far above the earth's surface is the satellite's orbit...
27. TOF (mass spectrometer) Analyzer Question

1. Homework Statement An unknown hydrocarbon ion required 9.415*10^-6 seconds to travel through the 0.250 T magnetic field of a mass spectrometer with a radius of curvature of 14.1 cm. Since the magnetic chamber is shaped like a 'D' it only travels half way around the circle. a. find the...
28. Frictionless Multiple Body Problem with Inclined planes

1. Homework Statement An m1 = 7.6 kg block and an m2 = 10.7 kg block, connected by a rope that passes over a frictionless peg, slide on frictionless incline. Find acceleration of boxes and tension of the rope. 2. Homework Equations F=ma I'm not sure what else 3. The Attempt at a Solution...
29. Frictional Force Direction Problem

1. Homework Statement The system is in equilibrium. All the surfaces in the image are rough. The direction of friction on B due to A is : (a) is upward (b) is downward (c) is zero (d) depends on the masses of A and B. ANS : (a) 2. Homework Equations MAg = 2μN (Friction due to wall and due...
30. SeniorPhysics Graded Assignment Help-Horizontal/Vertical Displacement

1. Homework Statement A student is rolling a baseball off the roof of their house into their backyard pool.The house is 20 feet tall, and they roll the baseball off the flat roof at speed of 3 m/s towards the pool. How long is the ball in the air and how far away is the distance the pool must...