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Properties of laser beam

What properties of a laser beam are used in: (a)holography- (b)punching holes in baby bottle (c)monitoring location of the crater of a dormant volcano by interferometry- (d)laying straight railroad tracks-

The Intensity of an Earthquake Wave

The intensity of a particular earthquake wave is measured to be 2.09à?106 W/m2 at a distance of 123 km from the source. What was the intensity when is passed a point only 4.39 km from the source? Give answer in W/m2.

Find noise from a helicopter rotor

The noise from a helicopter rotor is distributed equally in all directions. If the rotor generates 70 watts of sound power, find the intensity level of the sound in dB on the ground directly beneath the helicopter when its altitude is 120 m. Also find the altitude in meters for the sound to be reduced to 60 dB at the same locati

Power from Radium

It was stated that around the turn of the 20th century some researchers discovered that radium generated heat. Assuming that you have a pure 1 Ci sample of Ra-226, what is the maximum potential power (in Watts) that you could recover (at 100% efficiency) from this sample.

Lenses/compound microscope

Hi. Can someone please show me how to do the following problem? "The medium-powered objective lens in a laboratory microscope has a focal length f-objective = 4.00 mm. (a) If this lens produces a lateral magnification of -40.0, whiat is the distance from the object to the objective lens? (b) What is the focal length of an ey

Power and Resistance

A wire 1.2 m long and 0.4 mm diameter has a resistance of 4.9. Calculate the resistance of another wire of the same material whose length is 0.8 m and diameter is 0.24 mm.

Determine the Thermal Efficiency

A turboprop producing 1000 kW drives a propeller operating at 85% propulsive efficiency. If the fuel flow to the engine is 0.07 kg/s, determine the overall thermal efficiency of the engine.

Determine fuel flow

A turboprop engine produces a "Brake Specific Fuel Consumption" of 0.5 lb/bhp/hr. Determine the fuel flow (in kg/s) required at this bsfc to produce 800 bhp of power.


Hi, I need some assistance with the following physics problems. Please view the attachment to see the full set of questions.

Radioactive Decay as a Power Source

Strontium-90 is to be used in a radioisotopic thermoelectric generator (RTG) for powering a navigation beacon located in the arctic. a) How much of the Sr-90 activity is required to generate 50 W of electric power if the conversion efficiency from heat to electricity is 30%? Tip: You must take into account the fact that Sr-90


Air at 15°C is compressed steadily and isothermally from 100 kPa to 700 kPa at a rate of 0.12 kg/s. The minimum power input to the compressor is: 1.0 kW 11.2 kW 25.8 kW 19.3 kW

Translation operator problems.

The translation operator S(a), for arbitrary constant real vector a, is defined such that... a) Show, using the Taylor expansion of Φ(x-a) about x, that S(a) may be expressed in terms of the momentum operator p=.. Sum the expansion to give a simple closed-form expression for S(a). Please see attached for full question

Resistance and Current

The heating element of an electric broiler dissipates 2.8 kW of power when connected to a potential difference of 120 V. a. what is the resistance of the element? b. How much current does the broiler draw? use two ways to find out, and verify your answer.


Sam, whose mass is 75 kg, takes off across level snow on his jet-powered skis. The skis have a thrust of 200 N and a coefficient of kinetic friction on snow of 0.1. Unfortunately, the skis run out of fuel after only 10 s. What is Sam's top speed? (in meters/second)How far has Sam traveled when he finally coasts to a stop? (in me

Power Problem

A block with mass m has a coefficient of kinetic friction Mk with the floor. If the block is obeying Newton's 1st law while being pushed at angle 0 (theta), show that the power needed to push it at velocity v is given by P=Mkv(mg+fsin0)

Various Physics Problems

Hi, I am having trouble doing these problems listed below. Please show me how to solve these problems for future reference. Thank you very much. 1. You are told that the volume of a sphere is given by V = pie d/4, where V is the volume and d is the diameter of the sphere. Is this equation dimensionally correct? (Use SI unit

Resistors - Finding the Current

Hi. Can someone please help me with the following problem? I'll try to draw the circuit (with battery and 4 resistors), but I don't know if all the spacing will come out right. The "///" are resistors. Basically, it's a circuit with a 15-V battery and 4 resistors. First you hit R1, which = 11 ohms. Then there are two paths

RL Circuit: Calculating Power

Question: An ac generator with a frequency of 1.00 kHz and an rms voltage of 24 V is connected in series with a 2000 ohm resistor and a 0.365 H inductor. (a) What is the power factor for this circuit? (b) What is the average power consumed by this circuit?"

Resistors Networks

"Three resistors (R, 1/2R, 2R) are connected to a battery. (a) If the resistors are connected in series, which one has the greatest rate of energy dissipation? (b) Repeat part (a), this time assuming that the resistors are connected in parallel."

Average Power fun

Scott, riding for the Mercury team, won the 2002 Mt. Rushmore Hill Climb bicycle race with a winning time of 1 hour 50 minutes 20 seconds. The race is 28 miles in length with a total altitude gain of 7000ft. Scott weighs in at 130 lbs and his hill climbing bike weighs 17 lbs. The total weight of his water bottles, shoes, clot

Calculating resultant force and change in potential energy

The speed of a 4.0kg object is given by (2t) m/s, where t is in seconds. At what rate is the resultant force on this object doing work at t = 1 second? Answers: a) 48 W b) 40 W c) 56 W d) 16 W A 10kg object is initially at the top of a rise, at point A. It then moves down to point B. Choose point B to be your zero leve

Currents 4

1. A steam turbine at an electric power plant delivers 4500 kW of power to an electrical generator that converts 95 percent of this mechanical energy into electrical energy. What is the current delivered by the generator if it delivers energy at 3600 V? 2. A color television draws about 2.5 A when it is connected to

Work done in joules

A block of mass 5kg is lifted 2 meters in 3 seconds. Compute the work done in joules and in ergs.