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Engines and refrigerators

I have done an example to calculate the actual max efficiency of a power plant given the temperatures of both the hot and cold reservoirs. My book, however, tells me nothing about how to calculate any of the following questions. A power plant produces 1 GW of electricity, at an efficiency of 40%. (a) At what rate does th

Putting Prefixes in Order

Put these prefixes in order of increasing size. Put 1 for the smallest, 2 for the next largest, etc. 1. tera- 2. centi- 3. nano- 4. giga- 5. milli- 6. mega- 7. micro- 8. kilo-

Poynting vector from the antenna of a cell phone

An old analog hand-held cellular telephone operates in the 860 to 900 MHz band and has a power output of 0.600 W from an antenna 10.0 cm long. a. Find the average magnitude of the Poynting vector 4.00 cm from the antenna, at the location of a typical person's head. Assume that the antenna emits energy with cylindrical wave

Problem Set in Classical Physics

When a mass of 25.0 grams is suspended from a certain spring and lowered slowly until the spring stops stretching, the spring stretches 2.00 cm. What is the spring constant of the spring? a. 1.25 N/m b. 0.800 N/m c. 7.85 N/m d. 12.3 N/m A mass of 40.0 grams is attached to a vertical spring with a spring constant k = 2

Given total impulse and time, find average force

The engine of a model rocket is rated with a total impulse of 5.00 N seconds and a thrust duration of 1.20 seconds. What is the average force exerted by the engine? I believe the answer is 4.17 N. I need to see each step and formula to solve this question.

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.