# Energy

### Energy in Thermal Motion

A combination of 0.250 kg of water at 20.0 degrees C, 0.400kg of aluminum at 26.0 degrees C, and 0.100 kg of copper at 100 degrees C is mixed in an insulated container and allowed to come to thermal equilibrium. Neglect any energy transfer to or from the container and determine the final temperature of the mixture.

### Compton effect: Wavelength and energy of scattered photons

A beam of 0.700 nm photons scatters at 160.0 degrees from free electrons. What is the 1.) wavelength of the scattered photons? 2.) energy of each scattered photon?

### Chemical Potential and Gravitation potential: Anology

(See attached files for full problem descriptions)

### Energy required to create a rabbit "out of thin air".

This figure indicates the energy required to conjure up the rabbit "out of thin-air". Evidently it takes more than energy, U=E, of the rabbit. Please explain, and also tell me why these energies are called "Free". In other words, why did scientists give them such a name? Which figure is correct or are they both correct ?

### Oscillations, Frequency, Waves, Doppler Effect, etc

1. A 2kg block is attached to a spring and placed on a horizontal smooth surface. A horizontal force of 20N is required to hold the block at rest when it is pulled .2m from its equilibrium position. The block is released from its rest from this point, and is subsequently undergoes simple harmonic motion. Find a) the spring st

### A 0.5kg object is connected to a light spring with a spring constant of 25N/m and oscillates on a frictionless horizontal surface. the amplitude of motion is 3 cm.

A 0.5kg object is connected to a light spring with a spring constant of 25N/m and oscillates on a frictionless horizontal surface. the amplitude of motion is 3 cm. Find the total energy of the system. What is the speed of the object when the displacement is 2cm?

### Temperature and Heat of Metal

A metal ball of mass 0.65 kg with initial temperature of 30 oC is dropped into a container of 1.29 kg of water at 20 oC. If the final temperature is 20.4 oC, what is the specific heat of the metal to the nearest tenth of a J/kg·K?

### Calculating mass from kinetic energy

What is the mass of a man running at 5 m/s if he has a kinetic energy of 500 J?

### Frequency of Motion

Solid, uniform cylinder of mass m and radius R is fitted with a frictionless axle along the cylinder's long axis. A horizontal spring (spring constant k) is attached to this axle. Under the influence of the spring, the cylinder rolls back and forth without slipping on a horizontal surface. What is the frequency of this motion?

### Solving for the Kinetic Energy

A thin hoop with a radius of 10 cm and a mass of 3kg is rotating about its center with an angular speed of 3.5 rad/s. What is its kinetic energy?

### Physics problem about height, speed and gravity

What should the height of a slide in a park be so that a child will reach the bottom of the slide with a speed of 15 m/s using gravity as 10 m/s squared? Please include all work.

### Solving for Height

An 11 kg bowling ball is dropped into a tub containing a mixture of ice and water. A short time later, when a new equilibrium has been established, there are 5.0 g less ice. From what height was the ball dropped? Part A Assume the bowling ball has an initial temperature of 0 degreesC, and that no water or ice splashes out.

### Block Problems

1) A stationary block explodes into two pieces that slide along a frictionless floor and then into regions with friction, where they stop. The first piece, with a mass of 2.0 kg, encounters a coefficient of kinetic friction of 0.40 and slides to a stop in a distance 0.15 m. The second piece encounters a coefficient of kinetic fr

### Modern Physics: Energy, Compton wavelength, rest mass energy

I've attached a pdf file of the problem. I don't exactly know how to approach the question. I don't know exactly what the question is asking.

### Proton with Energy

(See attached file for full problem description) --- - Proton with energy 1.3 MeV is moving along a straight line ("0 degrees" in the figure) in the vacuum tube...

### Phototubes

Photo-tubes cut off (don't respond to photons) at sufficiently small wavelengths. This is because the photo-tube's glass does not transmit UV. They also cut off at sufficiently large wavelengths, where the glass does transmit the light. Why?

### Gaussian pulse propagating along a string, energy, momentum

For a Gaussian pulse propagating along a string, calculate kinetic and potential energies and momentum. See attached file for full problem description.

### Energy and momentum: Rolling, Collision and project.

The task is to determine where the metal ball will land. First ball will begin at rest and travel through a track and elastically collide with the metal ball. This metal ball will then is defenestrated and drop down. Also determine where the metal ball will land. Clear explanation of each step is needed. When it is done, it is a

### Potential energy and waves

A pulsed laser produces brief bursts of light. One such laser emits pulses that carry 0.350J of energy but last only 225fs. a) What is the average power during one of these pulses? b) Assuming the energy is emitted in a cylindrical beam of light 2.00mm in diameter, calculate the average intensity of one of the pulses? c) W

### Physics 8-3: Show how kinetic energy and particle mass are related; Magnitude of cardinal and baseball; Ratio of man's kinetic energy to woman's

8-3. a) Show that the kinetic energy K and the momentum magnitude p of a particle of mass m are related by K = p2/2m. b) A 0.040-kg cardinal (Richmondena cadinalis) and a 0.145-kg baseball have the same kinetic energy. Which has the greater magnitude of momentum? What is the ratio of the cardinal's magnitude of momentum to

### Rotational Inertia Problem

A uniform solid sphere of mass 5 kg and radius of 30 cm is rotating about an axis through its center at a rate of 180 rev/min. Find the kinetic energy of the sphere. The rotational inertia of the sphere is 2/d MR^2.

### Rotational Motion: Rod released on smooth horizontal plane

A thin rod of length h and mass M is held vertically with its lower end resting on a frictionless horizontal surface. The rod is then released to fall freely. Determine the speed of its center of mass just before it hits the horizontal surface. Use h, M, and g for length, mass, and gravitational acceleration respectively. (b)

### 3 Physics Problems

(See attached files for full problem description with units and diagrams) --- A package of mass is released from rest at a warehouse loading dock and slides down a 3.0-m-high frictionless chute to a waiting truck. Unfortunately, the truck driver went on a break without having removed the previous package, of mass 2 , from

### Motion in a vertical circle: conservation of energy

A pendulum consists of a string of length L and a bob of mass M. The string is brought to a horizontal position and given the minimum initial speed enabling a pendulum to make a full turn in the vertical plane. a) what is the maximum kinetic energy K of the bob? b) what is the tension in the string when the kinetic energy is

### How to calculate spring constant force

If an object with a mass of xkg on the end of a spring with a mass of ykg, is pulled 0.2 m away from equilibrium on a horizontal table and released where it achieves a max velocity of Zm/s at X=0, how do you calculate the spring constant?

### Collision in One Dimension

(See attached file for full problem description with diagrams and units) On a frictionless horizontal air table, puck A (with mass 0.369 ) is moving toward puck B (with mass 0.249 ), which is initially at rest. After the collision, puck A has velocity 0.116 to the left, and puck B has velocity 0.645 to the right. a)

### Determine the Rotational Kinetic Energy

A thin stick of length L = 1.6 m is denser at one end than at the other: Its mass density is = (0.40 kg/m) - (0.03 kg/m2)x, where x measures the distance from the heavier end of the stick. The stick rotates with period T = 1 s about an axis perpendicular to the stick through the heavy end. Determine the rotational kinetic energ

### What is that T?

Cold, interstellar, molecular clouds have been seen to contain the cynogen molecule, CN, whose first rotational excited states have an energy of 4.7*10^-4 eV above the ground state. There are actually 3 such excited states, all with the same energy. In 1941, studies of these molecular clouds, using the absorption of starlight pa

### A pair of bumper cars in an amusement park ride collide...

A pair of bumper cars in an amusement park ride collide elastically as one approaches the other directly from the rear. (see attachment for diagram) One has a mass of m1 = 464 kg and the other m2 = 560 kg, owing to differences in passenger mass. If the lighter one approaches at v1 = 4.32 m/s and the other is moving at v2 =