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Electric potential energy

Does the electric field always move from positive to negative? If I'm told that a uniform electric field of magnitude 4.1 x 10^5 N/C points in the positive x direction, and a 4.5 micro-C charge moves 6.0 m in the positive x direction, and to find the electric potential energy (which is -11 J), does my equation look like this:

Temperature and Kinetic Theory

Show that for a mixture of two gases at the same temperature, the ratio of the rms speeds of their molecules is equal to the inverse ratio of the square roots of their molecular masses.

Electromagnatism Induction of a Metal Bar

A metal bar with length L, mass m, and resistance R is placed on frictionless, metal rails that are inclined at an angle (Data) above the horizontal. The rails have negligible resistance. A uniform magnetic field of magnitude B is directed downward. The bar is released from rest and slides down the rails. a) Is the direction

Energy in Thermal Processes

Question: Three liquids are at temperatures of 10 degrees C, 20 degrees C and 30 degrees C, respectively. Equal masses of the first two liquids are mixed, and the equilibrium temperature is 17 degrees C. Equal masses of the second and third are then mixed, and the equilibrium temperature is 28 degrees C. Find the equilibri

Use of Bohr's model

Using Bohr Model determine: 1. energy loss when electron moves from orbit n=3 to n=1 2. calc wavelenght of the light when electron moves orbit from n=3 to n=1

Energy density in an electric field

A charge isolated metal sphere of diameter 10cm has a potential of 8000 V relative to V=0 at infinity. Calculate the energy density in the electric field near the surface of the sphere?

Energy Absorbance

A film badge worn by a radiologist indicates that she has received an absorbed dose of 2.3e-5 Gy. The mass of the radiologist is 67 kg. How much energy has she absorbed? Answer in mJ.

Answer in nm

A proton is located at a distance of 0.410 m from a point charge of +8.30 µC. The repulsive electric force moves the proton until it is at a distance of 1.56 m from the charge. Suppose that the electric potential energy lost by the system is carried off by a photon that is emitted during the process. What is its wavelength?

Atomic physics

Calculate the classical frequency for the light emitted by an atom. To do so, note that the frequency of revolution is v/2pir, where r is the Bohr radius. Show that as n approches infinity in f= 2pi2mk2e4/h3 times 2n-1/(n-a)2 n2 the expression varies as 1/n3 and reduces to the classical frequency.

Quantum Model

For two distinguishable, non-interacting particles in a box, Quantum Mechanics says the energy must be, for each individual particle, E = (h^2)/(8mL^2)*[(n_x)^2 + (n_y)^2 + (n_z)^2) where L is the length of one side of the cube, m is the mass of the particle, and the n's are independent integers that can take any value fr

Pogo Stick -- Kinetic Energy

Please see the attached file for full problem description. --- A child's pogo stick stores energy in a spring with a force constant of 2.50 x 10^4 N/m. At position A (XA= -0.100 m), the spring compression is a maximum and the child is momentarily at rest. At position B (Xb=0) the spring is relaxed and the child is moving u

Thermal Kinetic Energy Problem

As Fig. 8-44 shows, a 4.5 kg block is accelerated by a compressed spring whose spring constant is 640 N/m. After leaving the spring at the spring's relaxed length, the block travels over a horizontal surface, with a coefficient of kinetic friction of 0.25, for a distance of 5.9 m before stopping. (a) What is the increase in

Force Problem

The only force acting on a 2.4 kg body as it moves along the x axis varies as shown in Fig. 7-33 (attached). The velocity of the body at x = 0 is 4.0 m/s. (a) What is the kinetic energy of the body at x = 3.0 m? (b) At what value of x will the body have a kinetic energy of 8.0 J? (c) What is the maximum kinetic energy attai

Reading a Potiential Energy Curve

A single conservation force F(x) acts on a 1.0 kg particle that moves along an x-axis. The potential energy U(x) associated with F(x) is given by: U(x) = -4x e^(-x/4) J, where x is in meters. At x = 5.0m the particle has a kinetic energy of 2.0J. a) What is the mechanical energy of the system? b) Make a plot of U(x) as a

Inelastic collision causes loss of momentum

In physics lab we collided two objects that then both started moving in the same direction. We measured the velocities through two photo gates. We know momentum was lost because the velocities decreased after the collision. What are two physical reasons for the loss of momentum?

Interrupted pendulum

My professor was trying to explain the concept of the interrupted pendulum. I do not understand why most pendulums have the same period and why, when you interrupt a pendulum, it will still reach the same height.

Energy and quantum level

What is the energy of the photon emitted when the electron of a hydrogen atom makes a transition from the quantum level n=3 to the level n=1?

Find the Lagrangian function

Find the Lagrangian function. Please see the attachment. The bottom part of the attachment that got cut off just says "of motion of the particle."