Energy, Work & Power (25 of 31) Calculate the Average Power Output of an Accelerating Car

Рет қаралды 60,381

8 жыл бұрын

Shows how to calculate the average power output of the engine in an accelerating race car. Worked example.
Power is the rate a which work is done. Also stated as how fast work is done. Power is calculated as the amount of work done divided by the time it takes to do the specified amount of work. Power is directly proportional to the amount of work done and inversely proportional to the time it takes to do the work. Therefore, if the same amount of work is done over a shorter period of time then a greater amount of power is exerted. The SI unit for power is the watt.
You can link to all my videos at my website: www.stepbystepscience.com
Links to other power videos:
(1) Power, An Explanation
• Energy, Work & Power (...
(2) Power output when walking/running up stairs
• Energy, Work & Power (...
(3) Tower Crane Power Output
• Energy, Work & Power (...
(4) Power Output When Lifting an Object at a Known Velocity
• Energy, Work & Power (...
(5) Time to Lift an Object with Known Power Output
• Energy, Work & Power (...
(6) Power Output When Doing a Pull-up.
• Energy, Work & Power (...
(7) Comparing the Power Output of Two People
• Energy, Work & Power (...
(8) Power Output of a Car Engine with Constant Acceleration
• Energy, Work & Power (...
or
You can link to all my videos at my website: www.stepbystepscience.com

Пікірлер: 84

@siddheshnerurkar1167 3 жыл бұрын

thanks a ton , i had been messing up my power calculation by taking the final velocity in P=Fv. not the Avg velcoty. you solved my doubt thank you for uploading this

@stepbystepscience 3 жыл бұрын

So glad it helped!

@billwells8054 Жыл бұрын

Excellent, thank you! I have been using methods #1 and #2 and could not get them to agree. Duh! Method #2 always came out twice method #1. I had been using final speed, not average! Very well explained. Subscribed and many thumbs up!

@stepbystepscience Жыл бұрын

Glad this was helpful. Thanks for the great feedback and the sub.

@anthonydcosta8354 8 жыл бұрын

Thanks a lot, Sir it is really helping me prepare for my AP Physics.

@stepbystepscience 8 жыл бұрын

+#EVERYONEK Great, I hope the AP tests go well...You can see a listing of all my videos at my website, www.stepbystepscience.com

@devarakondapratyusha 6 жыл бұрын

Sir thank you very much for the video i used to think very hypothetically for my project but none of those things helped ,BUt when i gone through your video which is so simple i got all the answers needed for my project the other way around.

@stepbystepscience 6 жыл бұрын

Excellent, thanks for watching and commenting.

@luqmanpodolski4854 4 жыл бұрын

Thank you for the solution , really appreciate it 👍🏼

@stepbystepscience 4 жыл бұрын

No problem 👍, thanks for the comment.

@fhmtz 3 жыл бұрын

Excellent content, thank you!

@stepbystepscience 3 жыл бұрын

Glad it was helpful!

@jorgecalderon8649 8 жыл бұрын

Awesome! thank you very much!!!

@ashishkharw825 2 жыл бұрын

LOL

@LizBrown81 8 жыл бұрын

Cheers Mate, these vids are sweet. I am watching them to revise for my exams whilst running on a treadmill in a tiny village in England. Do you have any advice for remembering all the formulae?

@stepbystepscience 8 жыл бұрын

+LizBrown81 Thanks for watching, I'm sitting in my living room in Berlin Germany. Usually I give student an equation sheet for reference. Otherwise try always helpful flash cards.

@ahascointerprise5283 3 жыл бұрын

This helped me a loooooottttt👌👍

@stepbystepscience 3 жыл бұрын

Wonderful, glad to hear it!

@aparnabiswas6420 5 жыл бұрын

sir i have one problem, calculate the power of engine in watt which power is 2 horse power.

@smmoorthy 3 жыл бұрын

Excellent explanation, Thank you Sir

@stepbystepscience 3 жыл бұрын

Glad you liked it and thanks so much for the positive comment.

@aaronnicolas941 2 жыл бұрын

What to do if im only solving for power output not average output?

@codex7299 Жыл бұрын

Awesome video really loved the explanation and presentation of the working looking forward to more content🎉. just wanted to point out though that you put 160km/h on the question instead of 44.7m/s 😅 that might explain why your first comment on the video said that😅

@mariam33m 5 жыл бұрын

Your video taught me what I could not learn in 6 months, and I am very happy to watch the video, I am very grateful to you. GOD BLESS YOU❤

@stepbystepscience 5 жыл бұрын

Thanks for the great comment.

@ashishkharw825 2 жыл бұрын

LOL

@stevenestifanos7823 3 жыл бұрын

What would happen if they gave us the coefficient of friction for the road?

@dadejohnson6387 5 жыл бұрын

anyone can tell me how to find horespower of a car eperiencing a force of 1600lb moving 100meters in 7 secounds??

@Rudi1014 8 жыл бұрын

Thank you :)

@stepbystepscience 8 жыл бұрын

+Rudi1014 You are very welcome, thanks for commenting. You can see a listing of all my videos at my website, www.stepbystepscience.com

@mociczyczki 4 жыл бұрын

you calculation is good in vacum this aprticular car with this rear spoiler produce massive down force ;) which should be included into equation for real life average numbers :x just saying .

@wyskun 6 жыл бұрын

I have a very important 2 questions for me:) 1. In space, there is a space shuttle that does't move. Mass of this shuttle is always constant. This space shuttle has a rocket engine which produce a constant force of 100N. When the engine is started and the ship has a constant thrust of 100N, when the ship starts to accelerate, will the acceleration be constant and remain constant (let's assume 10m / s), or maybe the acceleration will start to decrease as the speed increases? It is related to the rule Ek = 1 / 2mv ^ 2 ??? 2. Same space shuttle doesnt move. Shuttle start to accelerate from 0km/h to 10km/h in 5 seconds and it takes "X" energy for example. How much energy it will needed to accelerate also 10km/h more in also in 5 seconds when it allready have velocity of 100km/h ? Also "X" energy? Or much more "X" of energy? And why is that?

@ajl2346 5 жыл бұрын

This might work in a class room but what you just calculated is not the total power. It is the amount of power that is being used to accelerate the car. The total power would have to include the power to overcome rolling resistance (rolling coefficient*mass* velocity) as well as the power to overcome aerodynamic drag( 0.5*CdA*air density*(velocity^3) ) if you wanted to make a real model. Good video though.

@faisalkhansasoli3777 8 жыл бұрын

sir I have one problem of work changes into P.E.When the mass of body covers distance in vertical line and for vertical line we put y.axis and for y.axis sin teta is used then why in work done changes into P.E we use cos teta?

@stepbystepscience 8 жыл бұрын

+Faisalkhan Sasoli I am sort but I do not fully understand your question. Work = fd cos (theta), I am not sure when you would use the sine. You can a listing of all my videos from my website, www.stepbystepscience.com

@faisalkhansasoli3777 8 жыл бұрын

Sir in Physics we have completely proved the work and I also know that Cos(theta) is used for its angle and on the other hand the confusion which I have is P.E that how work done can be changed into P.E? because in P.E height is distance and hight is along y.axis and for y.axis sin(theta) is used.

@saadjarad2882 Жыл бұрын

Thanks professor. What about the friction force and air resistance 🤔 force

@stepbystepscience Жыл бұрын

In these problems we ignore those factors.

@BalajiAddankiVidEd 6 жыл бұрын

Sir, what about frictional resistance between car tires and road (coefficient of friction is 0.7) . So some more power may required.

@stepbystepscience 6 жыл бұрын

I am not sure there is such a thing as "frictional resistance"

@BalajiAddankiVidEd 6 жыл бұрын

Sorry sir, I asked about real time problem. If car moving with constant velocity ( initial velocity = final velocity =120kmph, => a = 0 ), is that mean car generating no power??? Please someone tell me......

@maxchaikengdee7594 5 жыл бұрын

@@BalajiAddankiVidEd Yes, that is exactly what it means. According to Newton's 1. Law of motion, an object at which the net force is equal to 0, the ojbect most either be standing still or i a constant linear motion. Without accounting for drag and rollingresistance, there would be no force slowing it down, and since the motor acceleration is zero, the power output would be zero. Oh btw, your question regarding frictionalforce, is not the same for a rolling object, as for a flat object being dragged across the ground, obviously. You're gonna need the rolling coefficient instead of the frictional coifficient.

@brunocorrea6010 3 жыл бұрын

I know it's been two years, but I think this reply will be usefull The example of the video act as a real car doing a real acceleration. So, the car already did the 160kmh in 7,5s. Then, all resistances coming from tires and wind are already inbuilt in the math. The car needed an average of 214hp to move it's own weight with that set of tires trough the wind conditions of the day. Your thinking would be valid if we get the power at the wheels and had to calculate the estimated power before testing the car, not knowing how the wind and tires would be at the moment.

@waronamogobye436 Жыл бұрын

@@BalajiAddankiVidEd the engine is DEFINELETLY producing power. Just because the car is in equilirbrium does not mean the engine's force is to be neglected. It still exists and still does work, it's just that kinetic friction (i presume) does the exact same work in the opposite direction

@vineethkeralakumar3492 2 жыл бұрын

How can we account for work done in overcoming friction

@stepbystepscience 2 жыл бұрын

multiply the friction force x the distance.

@IanMocker 6 жыл бұрын

this video helped A LOT. thank you

@ashishkharw825 2 жыл бұрын

LOL

@pierremarcel8247 4 жыл бұрын

Thank you

@stepbystepscience 4 жыл бұрын

You're welcome

@ILOVECARTOONable 7 жыл бұрын

according to my conversion of 160 Kilometer per hour to meters per seconds is 44.44 m/s. How could that be 44.7 m/s? My answer in newton is 7, 116N.

@stepbystepscience 7 жыл бұрын

Don't be so nit picky!

@ILOVECARTOONable 7 жыл бұрын

Sorry.. Your videos sure help my report. I'm just checking my answer because maybe I am wrong. HAHAHA.. Pls don't mad at me :)

@loquitogusanito 6 жыл бұрын

I also did the calculations and ur right, he just assumed that 160km/hr was equivalent to 100mph (100mph =44.7mps) but alas its actually 44.4 and therefore all his other numbers are also slightly off

@MrFordmustanglover 7 жыл бұрын

Hello, why do you devide the velocity by 2?

@stepbystepscience 7 жыл бұрын

That gives you the average velocity.

@lisastakes7169 6 жыл бұрын

does anyone know how to calculate an unknown mass?

@stepbystepscience 6 жыл бұрын

What unknown mass?

@lisastakes7169 6 жыл бұрын

Step-by-Step Science in my physics class, we have a hw assignment where they give you horsepower, and a height, and a time but you have to solve for the unknown mass

@monoyous3505 3 жыл бұрын

Is the same engine put in a 2,000kg car produced the same horsepower?

@brunocorrea6010 3 жыл бұрын

Yes. But the acceleration would be slower. The same engine, in a heavier car, requires more time to reach the same speed. I did the math and would require 12,5s with the same 214hp of average power

@Sh4dowbanned Жыл бұрын

2:55: 160 kW?

@AhmedMohamed-vd6tj 7 жыл бұрын

you are awesome teacher But I hope that you can reorder your videos in your playlists and put them in new separate playlists so that I can access easily and faster for example instead of puting whole mechanics in one playlisy I hope that you can divide it into for example kinematics or one dimensional motion in separate playlist and two dimensional motion also and so on (as our boiling books syllabus ) hope that I illustrated my suggestion for you goodly because I am arabic (my english is bad)

@stepbystepscience 7 жыл бұрын

Thank you for the excellent comments. I have recently made some playlists for my channel and will make more...but you can also see a listing of all my videos at my website,www.stepbystepscience.com Excellent English by the way!

@AhmedMohamed-vd6tj 7 жыл бұрын

thank you for replying me directly .Now I can access them easily from website .You know I like you ,khan academy, coursera, edx, mit,teded and so on . high quality education for free to poor like us .keep going I will ask allah that can help you in your career . can you tell me how I can improve my english so I can get ilets degree .

@stepbystepscience 7 жыл бұрын

I believe everybody should have an equal opportunity to learn. I am an currently living in Berlin, Germany trying to become fluent in Germany....it is hard learning a new language. Of course the best is to speak English a often as possible. I think it is also good to watch some TV/videos etc and listen to the radio. Your English is very good.

@weixiongneo 3 жыл бұрын

how do you get 22.4m/s in 3:00 mins? Please help me!!! My exams is in 1hrs time :(((

@stepbystepscience 3 жыл бұрын

As I said in the video, 160 km/h = 100 mph = 44.7 m/s...for the equation you need the average velocity which you can take as half of 44.7 m/s = 22.4 m/s. Does that help? and good luck with the test!

@AzN1337c0d3r 3 жыл бұрын

The distance calculation here isn't correct unless the car is accelerating uniformly the entire time, which isn't true for constant power output. At a constant power output, a car will initially accelerate very fast and slow down towards the end. This leads to a change in the distance traveled.