Explore BrainMass


Energy in the field of charged conducting sphere

A conducting sphere of radius R carries a charge Q. a) Calculate stored energy b) Calculate the radius R(sub 0.5) within which the field energy is one half the total stored energy. c) Calculate the radius R(sub0.9)

Speed of object after it is ejected by spring

A block of mass m slides without friction on a table with speed v. It hits and compresses a spring of force constant k by a distance l. The spring then expands again ejecting the block in the opposite direction as it was originally traveling. Neglecting the mass of the spring, what is the speed of the object after it is ejected

Number of Photos, Wavelength, Maximum Energy and Velocity

1. A candle flame can be seen at night at a distance of 2 km by the unaided eye. If it emits visible light at the rate of 0.02 J/s, what is the number of photons that enter the eye per second? 2. What is the wavelength of a beam of ultraviolet light if its photon energy is 10 eV? If the beam produces photoelectrons from iron,

Classical Mechanics Homework

A block of mass m: I.62 kg slides down a frictionless incline (attached). The block is released a height h : 3.91m above the bottom of the loop. See attached for full problem description.

Bose-Einstein condensate of atoms in a potential well.

This exercise is for a Bose-Einstein condensate of indistinguishable atoms which do not interact with each other and are in a 3-dimensional harmonic well. The system is described by the following Hamiltonian (see attached file).

Kinetic Energy

A stone of mass 0.62kg is fired upwards at an angle to the ground and with a speed of 5.5 m s-1, as shown in the figure in the attachment. The figure shows the path of the stone until it strikes the ground at point C. Disregard air resistance. Take the acceleration, g, due to gravity to have a value of 9.8 m s-2. Calculate

Power and Energy

A perfectly insulated container contains 70 g of water and has a small heater immersed in water. The temperature of the water is 40 degrees Celsius, and the heater is connected to a 12V battery via a switch. When the heater is switched on, an electric current of 13A flows through its heating element and the temperature of the w

Speed of mass

A 20.0-gram mass is attached to a 120 cm-long string as shown in Figure 6-7. The angle theta is measured to be 18.0 degrees. What is the speed of the mass? 1.95 m/s 3.82 m/s 1.18 m/s 1.09 m/s

Electricity and Magnetism Problems

Problem A): Consider the railgun shown below: See attached file for full problem description. Consider a 1 kilogram projectile that is accelerated using a 10 meter long, 3 cm wide, railgun with a 1 million amp constant current pulse. 1) Derive an analytic expression for B everywhere in the plane between two infinitely

Simple harmonic motion

See attached file for full problem description. 1. Consider the four equivalent ways to represent simple harmonic motion in one dimension: To make sure you understand all of these, show that they are equivalent by proving the following implications: I-->II--> III--> IV. For each form, given an expression for the constants (C

Rocket Propulsion

Rocket Propulsion. See attached file for full problem description. A rocket is fired from a space station that is 1000 miles above the surface of the Earth. We take the radius of the Earth to be 4000 miles, so r = 5000 miles. Suppose that the rocket is fired "horizontally". That is, suppose at the time the rocket is launched.

Maximum height of a spring

In problem 13.61(a), if the spring constant k is 30 N/m, and the collar C has 350-g, the maximum height above point B reached by the collar is: a. 0.198 m b. 0.291 m c. 0.306 m d. 0.148 m

Energy Conservation Calculation

A 1.0 kg block is shot up a 30* incline with an initial speed of 400cm/s. How far up the incline will the block go before sliding back down if the coefficient of kinetic friction between the block and the incline is 0.17? Use the principle of energy conservation in the analysis and solution.

Probability of a single-particle state being occupied.

For a system of fermions at room temperature, compute the probability of a single-particle state being occupied if its energy is (a) 1 eV less than mu. (b) 0.01 eV less than mu. (c) equal to mu. (d) 0.01 eV greater than mu. (e) 1 eV greater than mu.

Partition Function

Consider a hypothetical atom that has just two states: a ground state with energy zero and an excited state with energy 2 eV. Draw a graph of the partition function for this system as a function of temperature, and evaluate the partition function numerically at T = 300 K, 3000 K, 30,000 K, and 300,000 K.

Photoelectron Multiple Choice Problem

In an experiment different wavelengths of light, all able to eject photoelectrons, shine on a freshly prepared (oxide-free) zinc surface. Which statement is true? a. The number of photoelectrons emitted per second is independent of the intensity of the light for all the different wavelengths. b. The number of photoelectrons em

Calculating Potential, Kinetic, and Total Energies

You are at the top of a 500 meter tower and drop a 5-kg hammer. Calculate the potential and kinetic energies and total energy at the end of each second of free fall and at the moment of impact. Elasped D=5t2 V= a t PE = mgh KE =1/2 mv2 KE + PE mv Time m m/s

One dimensional infinite square well potential.

a) Show that the classical probability distribution function for a particle in a one dimensional infinite square well potential of length L is given by P(x) = 1/L b) Use the result from part (a) to find the expectation value for X and the expectation value for X^2 for a classical particle in such a well.

Pendulum and Spring Questions

____ 1. A simple pendulum, 2.0 m in length, is released with a push when the support string is at an angle of 25 deegree from the vertical. If the initial speed of the suspended mass is 1.2 m/s when at the release point, what is its speed at the bottom of the swing? (g = 9.8 m/s2) a. 2.3 m/s b. 2.6 m/s c. 2.0 m/s d. 1.8 m/

energies at the end of each second of free fall

You are at the top of a 500 meter tower and drop a 5kg hammer. Calculate the potential and kinetic energies and total energy at the end of each second of free fall and at the moment of impact. t D=5t2 V=at PE=mgh KE=1/2mv2 Elapse Distance Do

The motion of spring when the length of string shortened

Consider a simple plane pendulum consisting of a mass m connected to a string of length L. After the pendulum is set in motion , the length of the string is shortened at a constant rate: dL/dt = -k The suspension point remains fixed. Compute the following: a) The Lagrangian and Hamiltonian functions b) Compare

Gravitational potential energy

Relative to the ground, what is the gravitational potential energy of a 55.0 kg person who is at the top of the Sears Tower, a height of 443 m above the ground?