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Power delivered to a resistor

Four resistors are connected to a battery with a terminal voltage of 15 V, as shown in attached figure. Determine the power delivered to R2. (R1 = 20 ohm;, R2 = 45 ohm)

Electrical energy and potential energy

A portable CD player uses a current of 7.2 mA at a potential difference of 3.5 V. Suppose the player has a mass of 0.47 kg. How long could the player operate (in minutes) on the energy required to lift it through a height of 1 m?

Modern Physics with de-Broglie and Electron Microscope

1. Wavelength of particles a. Consider a dust particle of diameter d =1 micron, mass m= 10^-15 kg, and speed v = 1 mm/s. Calculate the de Broglie wavelength of the particle and compare with the particle's size. b. Now consider a thermal neutron, i.e, a neutron (m=1.67 x 10^-27 kg) with a speed corresponding to the average the

Velocity and Acceleration Positivity

I need help with the following two problems in the attachment. How do I tell if velocity and acceleration are positive, negative or zero? Please see the attached file. Thanks

Dimensional Analysis, Vectors, etc.

Please see instructions on attachment. Please solve each and give a complete detailed step by step solution to solving each problem no matter how easy. I am trying to learn and not an expert. Give answer and way to solve. Adult student trying to make my way through all this and need your help! 1) A flat circular plate o

Wavelength of wave

The vertical displacement of a string is given by y(x,t) = (6.00mm) cos[(3.25m to the power of (-1)) x - (7.22 s to the power of (-1))t]. What is the wavelength of the wave?

Freqency of motion

The position of a mass that is oscillating on a spring is given by x=(18.3 cm) cos[(2.35s to the power of -1)t]. What is the freqency of this motion?

Power/Current Required

An X-ray machine operates from a 220V supply. The machine power is 800W and the supply must also supply six 24W, 220V indicator lights. Please answer all questions with full explanations thankyou 1) What is the total power required? 2) What is the current drawn from the 220V supply? 3) A transformer with 250 turns in

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