Power output Definition and 138 Threads

A load has a power rating of 160 w when the current is 6.0 A. What will be the power output if the current increases to 15 A? I know how to do it : use the formula v=I^2R In this case 15/6 = 2.5^2 = 6.25 160 * 6.25 = 1000W. My question is why can't you use p = VI ? Because in this case , it...

I trying to come up with a way to measure the power output of an engine using a water pump, And I wanted some one to go over my math and check for flaws in my thoughts. My idea is to measure the flow rate and the pressure of the output of the water pump. Using this math to solve for power...

Homework Statement A small motor is used to operate a lift that raises a load of bricks weighing 500N to a height of 10m in 40s at constant speed. The lift weighs 300N. What is the work done by the force of the motor? What is the work done by the force of gravity? Homework Equations P...

Hi guys, I have to calculate de optical power output of a set of LEDs. For that I used a photodiode to measure the photocurrent at each wavelength and then calculate the optical power at each wavelength using the following formula: R (A/W) = I/P, where R is the responsivity of the...

Homework Statement 620 seconds after starting its take-off, a 260000 kg jet reaches its cruising altitude of 9200 meters and flies with a speed of 235 m/s. Neglecting friction, what has been the average power output of the engines? Homework Equations ΔKE = Work Power = Work/time...

Homework Statement "How does the placement of the puncture hole of a stearin engine affect the power output of the system?" By a stearin engine, it just means an oscillating candle around a fixed point; a video can be viewed at . I have done all of the data collection by testing...

Homework Statement I have to analyse the power output of a solar panel using a basic electrical engineering circuit analysis of a solar module if a complete row of solar cells in it is shadowed (For example, such shading might be caused by dust that slides down the surface of inclined panels.)...

Homework Statement Figure 29 shows a battery connected across a uniform resistor R0. A sliding contact can move across the resistor from x=0 at the left to x=10 cm at the right. Find an expression for the power dissipated in the resistor R as a function of x. Plot the function for ℰ=50 V...

Homework Statement How do I find the answer for part C? 3) A battery with an Emf of 12 volts is hooked up to a 125 ohm resistor and an ammeter. The ammeter measures a current of 75 mA. a) Calculate the internal resistance of the battery and the actual voltage across the battery. b) Calculate...

I'm trying to think of a way to calculate the power output of a solar panel by taking in information from hourly weather data from weather.com (e.g. sunny or cloudy?, temperature, etc.) and basic characteristics of the location and panels, but i cannot find or think of a way to do so. Basically...

Hi, I want to use piezoelectric material to harvest compression energy, i need to calculate the power output but i can't find enough information on the web to figure it out... First, I want to learn how to calculate the power output of piezoelectric material using d33 and g33 data...

How much power would be produced when using an independently powered supply of 100 pound/min air at 3bar/40F air on a 6.2L GM LS V8. Excess air will be vented to atmosphere with relief valves to stabilize the air flow to the throttle valve. What are the factors need to be considered...

The weather got warm enough for me to go for a bike ride on Saturday on a favorite route. As summer and early fall are long behind me I am not in as good of shape as back then. Riding my bike up a particularly steep hill and trying not to push stupid hard I was a bit depressed at the state of my...

How do I convert the RPMs of a simple turbine (e. g. a windmill) into the power it generates? Let's say that I want to know if a single windmill of a certain size can power a refrigerator. Assume that I already know how long the blades have to be to produce the RPMs, and I know the energy...

Homework Statement Hi all! I am been working on an EEI. Basically I recorded the power output (P=VI) of a wind turbine with the blades at different angles. I went from 0 degrees (flat) to 180 degrees in 15 degree increments. Averaging the data I see a graph like this: Also, just to...

Homework Statement A coal power plant with 30% efficiency burns 10 kilograms of coal per day. (Take the heat of combustion of coal to be 30 MJ/kg) a) what is the power output of the plant? b) At what rate is thermal energy being discarded by this plant? c) If the thermal energy is carried...

Homework Statement I'm studying for my GCSE exam and I need to know how changing the voltage across a bulb affect it's power output for my secondary evidence, i have searched the internet for the answer but can't find anything. Anyone know how it affects it OR any useful websites to use...

Hello everyone! This is my first time posting here and I hope I can make a good first impression, and I apologize for the lack of links because of this being my first post. Currently I am working on a project for my grandfather's engineering business, and part of this project is designing a...

Total Power output Sound! All right, nevermind, problem resumed. . A rock band has an average intensity level of 110 dB at a distance of 15 m from the speakers. Assuming the sound is radiated equally over a hemisphere in front of the band, what is the total power output? Relevant...

Hi I'm just thinking over a few things and realized there's something pretty fundamental that doesn't seem to get explained often or at least very well. Maybe I'm too much of a novice, who knows...anyway... When a power supply states a power output of say, 750W, what exactly does that...

A small steel wire of diameter 1.4 mm is connected to an oscillator and is under a tension of 6.3 N . The frequency of the oscillator is 63.0 Hz and it is observed that the amplitude of the wave on the steel wire is 0.50 cm. a)What is the power output of the oscillator, assuming that the wave...

Homework Statement A cyclist coasts down a 7.2 degree hill at a steady speed of 10 km/h. If the total mass of the bike and rider is 75 kg, what power output must the rider have to climb the hill at the same speed? Homework Equations Power = Energy/Time Ek = 1/2mv^2 where m is the mass...

Homework Statement In order for a car of 4000kg to travel at 10m/s with a frictional force of 400N, find the power output of the engine. Homework Equations P=Fv The Attempt at a Solution I found 40000*10+400*10=400400W, is this right?

A man runs up 1576 steps in 9minutes 33sec. If the height gain of each step was 0.20m, and the mass of the runner was 70.0kgs, what was average power output during climb? I used P=W/T & W=FD W=70kg(1576)0.20=22,064J P= 22,064J/573s = 38.5 W answer given is380W What am I missing?

Homework Statement Humans have about v = 60 cm3 of blood per kilogram of body mass and blood makes a complete circuit in t = 20 s seconds. For a human body of thickness 0.2 m and height 1.8 m, estimate the change in power output of the heart when the body is standing up on a horizontal...

Homework Statement A bicyclist coasts down a 7.0 degree slope at a steady speed of 5.0 m/s. Assuming a total mass of 75 kg (bicycle plus rider), what must the cyclist's power output be to pedal up the same slope at the same speed? Homework Equations P=Fvcos\theta K=\frac{1}{2}mv^2...

How to find power required for adiabatic compressor? Problem - Air enters an adiabatic compressor at 20 C and 1bar. The volumetric flow rate of air is 1 m3/s and it exits at 200 C. Determine the power required if the isentropic efficiency of the compressor is 80%. Density of water = 1000...

Homework Statement The question wants us to determine what the power output of a 2.32 GHz geosynchronous satellite that has an antenna gain of 18 dB be for a mobile receiver that is operating with an effective antenna gain of 3 dB in order to achieve the FM threshold (6 dB).Homework Equations...

Hi, I'm new here and I apologize up front if my terminology is incorrect. I've been a Civil Engineer for over 30 years, but am very far from an expert in electrical. Sorry if this is an elementary school level question for you guys! I am hoping someone here can either give me a hand or point me...

Homework Statement a) An electrical device stores energy in a 1.25 x 10^-4 F capacitor at 220 V. How much energy can be stored in this device? b) If 1.25 J were released from capacitor in 0.25 second, what would be its power output? I believe I solved (a), but I cannot find out how to...

Homework Statement a person ran 100m in 9.69 seconds. assuming the acceleration was constant, what was his average power output during that run in watts? Homework Equations P=Fd/t or P= change in energy/t The Attempt at a Solution i don't actually know where to start... i know i...

Homework Statement A car battery with 12V EMF charged to 120amp hours. Assume potential difference across terminals is constant. How long can the battery deliver energy at a rate of 100Watts. Missing is current (i), internat resistance (r), and real voltage (Vr)Homework Equations (Amp...

hey guy I was wondering if there was any way to increase the amperage output of an ac to dc converter, it is a 120v ac input that outputs 13v dc at 3.42 A. is there any way to boost this output? P.S. Ya'll are the best, This is by far one of my favorite places to be on the web. kudos on a job...

Homework Statement The hot reservoir of a heat engine is steam at 100 Celsius while the cold reservoir is ice at 0Celsius In 1.4 hours of operation, 12 kg of steam condenses and 60 kg of ice melts. What is the power output of the heat engine? Homework Equations Efficiency =...

An object with a mass M is rotating around an axis, with an arm of radius R at a certain speed V. Assuming that the movement is constant, and a 100% efficiency, how many watt of electrical power can this device generate ? For example purpose, we can take M=60 kg, R=5 meters and V=10 meters...

Homework Statement Thought it'd be easier to post the problem statement rather than writing it down again.http://imgur.com/TE2kN.png" The Attempt at a Solution I'm trying to get b and c. For b I have: \frac{mgd}{\Delta t_{one flap}}=\frac{\frac{1}{2}m(v_f ^2 -v_i ^2)}{\Delta t}...

Homework Statement The hot reservoir of a heat engine is steam at 100^ C while the cold reservoir is ice at 0 C. In 1.3 hr of operation, 11 kg of steam condenses and 52 kg of ice melts. Homework Equations I think power output is W=Qin-Qout The Attempt at a Solution I believe the...

This is not really homework, it's just something I don't understand and I will be assessed on it soon, so I need some help on it. First off our teacher is the worst teacher you will ever encounter, he gives us the solution but doesn't tell us how (tells us to figure it out ourselves). I tried...

1.)what is the power output of a 1200kg car that can go from 25 km/hr to 100 km/hr in 12 secs. Neglecting air resistance and rolling friction. 2.)a woman skis down a slope 300ft high. her speed at the foot of the slope is 60 ft/sec. what percentage of her initial potential energy was dissipated?

Homework Statement what is the average power output of an engine lifts a 250kg mass a distance of 30.0m in 20.0s? Homework Equations Ek= (1/2)(m)(v^2) Ep=mgh Ew=fnet x distance Es= (1/2)kx^2 The Attempt at a Solution Ep+Ek=f x d (.5)(200)(3)^2 + (200)(9.81)(5)= fx5.00...

Homework Statement A 48.0 kg sprinter, starting from rest, runs 46.0 m in 7.30 s at constant acceleration. a) What is the magnitude of the horizontal force acting on the sprinter? b) What is the sprinter's power output at 1.70 s? Homework Equations x=x_0 + v_0 t + \frac{1}{2}at^2...

Homework Statement At a coal-burning power plant a steam turbine is operated with a power output of 491 MW. The thermal efficiency of the power plant is 39.0%. (a) At what rate is heat discarded to the environment by this power plant? ______ GW (b) At what rate must heat be supplied to...

Homework Statement If a man has an average useful power output of 41.4 W, what minimum time would it take him to lift fifty 15.0-kg boxes to a height of 1.88 m? Homework Equations 1/2mv(final)^2 mgy(final) = 1/2mv(initial)^2 mgy(initial) P=W/Δt P=Fv The Attempt at a Solution...

Homework Statement A car with mass 1000 kg accelerates from 0 m/s to 40 m/s in 10.0 s. Ignoring air resistance. The engine has a 22% efficiency, which means that 22% of the thermal energy released by the burning gasoline is converted into mechanical energy. a) What is the average...

Homework Statement A 580w heater is designed for use in Germany, where electric outlets supply 230V(rms) service. What is the power output of the heater when plugged into a 120V(rms) outlet in the U.S.? Ignore the effects of temperature on the heater's resistance. Homework Equations...

Homework Statement Calculate the power output of a 1.8-g spider(the black dot) as it walks up a windowpane at 2.3 cm/s. The spider walks on a path that is at 25^{o} to the vertical as illustrated below. http://img19.imageshack.us/img19/4107/spiderl.jpg Homework Equations P = W/t F =...

I'm a bit confused about power output and gear ratios. I think it's best to explain by going by my example (imperical units, sorry Americas & Brits): Mass: 1300kg max. power: 128 kW @ 5500 rpm max. torque: 245 Nm Gear ratios (from a slightly different car type, but should be similar): 1st...

To send a signal, how much power does the microwave transmitter use?

Hi, I have a small DC dynamo (with no spec sheet) which i digitally sample to find it's voltage at any given time. I want to display theoretical max power output, how can I calculate this? Can I use P=V^2/R where V is measured. How do I calculate R? I read a wikipedia article which says to...

Homework Statement A solar-thermal power plant is to be built in a desert location where the only source of cooling water is a small creek with average flow rate of 100kg/s and an average temperature of 30 degrees C. The plant is to cool itself by boiling away the entire creek. If the...