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# Energy

### 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 =

### Conservation of momentum and energy: A 0.420 kg ice puck, moving east with a speed of 3.04 m/s...

A 0.420 kg ice puck, moving east with a speed of 3.04 m/s, has a head-on collision with a 0.930 kg puck initially at rest. Assuming a perfectly elastic collision, what is the speed of the lighter puck? Use east as the positive axis.

### Drop height to achieve known deflection in a beam

A .5m long beam with 29N-m stiffness is attached to a 45kg weight. The beam is inclined 30 degrees from vertical. Assume the beam has no mass, assume the 45kg weight is "sliding" down a vertical pole of infinite stiffness and zero friction. The mass is dropped and the end of the beam deflects .095m when it contacts the ground.

### Physics problem

A potter's wheel -- a thick stone disk of radius 0.500 m and mass 100 kg -- is freely rotating at 50.0 rev/min. The potter can stop the wheel in 6.00 s by pressing a wet rag against the rim and exerting a radially inward force of 65.0 N. Find the effective coefficient of kinetic friction between the wheel and the rag.

### An electron with a speed 5.00x10^8 cm/s enters an electric field of magnitude 1.00x10^3 N/C, traveling along a field line in the direction that retards its motion. (a) how far will the electron travel in the field before stopping momentarily, and (b) how much time will have elapsed? (c) If the region containing the electric field is .08m long, what fraction of the electron's initial kinetic energy will be lost in that region?

An electron with a speed 5.00x10^8 cm/s enters an electric field of magnitude 1.00x10^3 N/C, traveling along a field line in the direction that retards its motion. (a) how far will the electron travel in the field before stopping momentarily, and (b) how much time will have elapsed? (c) If the region containing the electric fiel

### What is the flux density of magnetic path?

Assume that the energy stored in the air gap is 1.5 J. What is the flux density of magnetic path? ( Hint: Convert to proper units) 1) 0.007 Wb/m^2 2) 0.350 Wb/m^2 3) 1.70 Wb/m^2 4) 4.24 Wb/m^2 (Please see the attachment for the diagram)

### Potential and Kinetic energy of an oscillator

A block of mass m = 0.65 kg is fastened to a spring with k = 65 N/m. The block is pulled a distance x = 11 cm from its equilibrium position at x = 0 on a frictionless surface and released from rest at t = 0. v= 1.1 m/s^2 Calculate the potential and kinetic energy of the oscillator when the block is at x = 0.

### Potential Difference: Particle Change, Lightning Discharge Etc.

Please show all work and show all equations used and diagrams. 1) If 500J of work are required to carry a 40C charge from one point to another the potential difference between these two points is: 3) The potential difference between two points is 100V. If a particle with a charge of 2C is transported from one of these poi

### Understanding the Human Ear

The radius of a typical human eardrum is about 4.0 mm. Find the energy per second received by an eardrum when it listens to sound that is (a) at the threshold of hearing and (b) at the threshold of pain.

### Find the kinetic energy

Find the kinetic energy of a cylindrical shaft of mass 2.0 kg and radius 10cm rotating about its central axis at 600 rad/s a. 1800 j b. 1200 j c. 18000 j d. 12000 j

### Kinetic energy

A neutron in a nuclear reactor makes an elastic head-on collision with the nucleus of a uranium atom initially at rest. (a) What fraction of the neutron's kinetic energy is transferred to the uranium nucleus? (The mass of the uranium nucleus is about 238 times the mass of the neutron.) (b) If the initial kinetic energy of

### Rotational Dynamics

A solid sphere of mass 1.0 kg and radius of .10 m rolls down a 10 m board which makes an angle of 30 degrees to the ground. (a) What will be sphere's speed when it reaches the ground? (b) What will be its rotational speed? (c) What total energy will it have?

### Energy and Momentum - Child on a Swing

See the attachment for a diagram of the scenario below. A child with a mass of 22 kg sits on a swing and is held in the position shown by a second child. (35 deg from vertical). Neglecting the mass of the swing, determine the tension in rope AB... a) while the second child holds the swing with his arms outstretched horizont

### One dimension collisions

A ball of mass 1.5kg is thrown upward. it leaves the thrower's hand with a velocity of 10 m/s. Assuming the upward direction is positive: a. how long does it take for the ball to return to the throwers hand b.what is the ball's final velocity just before it reaches the hand? c. what is the change in momentum of the ball?

### Propulsive Efficiency

Propulsive efficiency can be defined as the useful power output over the rate of change in energy of the airflow through the engine. If useful power is thrust x velocity, and the rate of change of KE is expressed in terms of air mass flow rate, provide an expression for &#951;P in these terms. If the efflux pressure is brought

### Derive Expression Where Needed

1. A motorcyclist is coasting with the engine off at a steady speed 17 m/s but enters a sandy stretch where the coefficient of friction is .80. Will the cyclist emerge from the sandy stretch without having to start the engine if the sand lasts for 15 m. If so, what will be the speed upon emerging? 2. One car has twice the

### Weather Forecasts Physical Origins

Question: It is the middle of winter and the weatherman forecasts a cold, overcast, but dry day, with an average temperatures of -2 degrees Celsius. However, he highlights the presence of a strong wind with a wind chill factor that will make it feel like -10 degrees Celsius. What is meant by the term 'wind chill'? How can it be

### Elastic and Inelastic Collisions

A 10 gram bullet is fired horizontally into, and becomes embedded in, a suspended block of wood whose mass is 0.890 kg. (a) How does the speed of the block with the embedded bullet immediately after the collision compare with the initial speed of the bullet? (b) If the block with the embedded bullet swings upward and its center

### Relative Motion : Kinetic and potential energy

You (A) are in a sledge sliding down an inclined plane. (Friction is neglected). An observer (B) at the foot of the plane looks at your initial position at the top of the slide and sees your energy as potential energy (mgh). You (A) slide down to the bottom of the plane and have a velocity of V0. So the observer sees mgh = mV0

### Thermodynamics

An ideal gas mixture consists of 3 kg of Ar and 6 kg of CO2 gases. The mixture is now heated at constant volume from 250 K to 350 K. The amount of heat transfer is:

### Mixed Energy Photon Beam

A collimated gamma ray beam consists of equal numbers of 0.1 MeV and 1.0 MeV photons. If the beam enters a 15 cm thick concrete shield, what is the relative portion of 1 MeV photons to 0.1 MeV photons in the emergent beam?

### Finding the lagrangian of a system

A triangular piece of wood is free to slide, without friction, in one dimension along a table, forming a moving inclined plane. A block of wood, placed on this inclined plane only moves as the result of the triangular block moving. There is no friction between the triangular piece of wood and the block. Find the lagrangian fo

### Find the wavelength of the electron.

Find the wavelength of an electron with energy E = 2MeV. [Hint: The deBroglie relation lambda = h/p is correct at all energies, but since this energy is relativistic, you will have to use the relation E^2 = (pc)^2 + (mc^2)^2 to find p.]

### Electrical Potential Energy

A 100-µF parallel-plate capacitor is charged to 500 V. It is then disconnected from the charging source and insulated. (a) How much energy is stored on the capacitor? (b) If the plates are pulled apart to a separation that is twice their initial separation, what energy is stored on the capacitor? (c) If the answers are not i

### Special Relativity and Schwarzschild Radius

1. A particle is measured to have a kinetic energy that is four times its rest as energy. How fast is the particle moving? Express the speed as a fraction of c. 2. Write down the transformations that relate the electric field E and the magnetic field B in two different inertial frames. Use your result to show that E*B is the

### Maxwell-Boltzmann Translational Energy Distribution

Sketch (schematically) the Maxwell-Boltzmann translational energy distribution and label the energy axis as best you can in any energy units that you choose. I am looking for a graph. You can sketch it by hand and scan or take a digital photo if you wish, and I'd like to know where the Maximum of the curve is on the X-axis (

### Simple Harmonic Motion Springs

A 165 g mass attached to a horizontal spring oscillates at a frequency of 2.80 Hz. At t=0 seconds, the mass is at x=5.20 cm and has v_x = -42.0 cm/s. Determine: A) The period in seconds B) The angular frequency is rad/s C) The amplitude in meters D) The phase constant in rad E) The maximum speed in m/s F) The maximum acc

### Displacement of a Mass on a Spring

a) When the displacement of a mass on a spring is 1/2*A the half of the amplitude, what fraction of the energy is kinetic energy? Express your answer as a percent. b) At what displacement, as a fraction of A, is the energy half kinetic and half potential?

### Oscillator and Amplitude: Example Problem

An oscillator with a mass of 500g and a period of 1s has an amplitude that decreases by 2% during each complete oscillation. A) If the initial amplitude is 9.6 cm, what will be the amplitude after 48 oscillations? Express your answer in centimetres. B) At what time will the energy be reduced to 29 percent of its initial val

### temperature and phase changes in making iced tea

See attached file. Calorimetry involving temperature and phase changes in making iced tea. PSS 17.2: Making the Iced Tea Learning Goal: To practice Problem-Solving Strategy 17.2 for calorimetry problems involving temperature and phase changes. On a hot summer day, you decide to make some iced tea. First, you brew a volum