suppose-you-read-about-a-new-car-that-can-go-from-0-to-100-mathrmkm-mathrmh-in-only-20-seconds-what-

Question

Suppose you read about a new car that can go from 0 to $100 \mathrm{km} / \mathrm{h}$ in only 2.0 seconds. What is this car's acceleration?
a. about $50 \mathrm{km} / \mathrm{h}$
b. about $14 \mathrm{m} / \mathrm{s}^{2}$
c. about $50 \mathrm{km} / \mathrm{s}^{2}$
d. about $200 \mathrm{km}$
e. about $0.056 \mathrm{km} / \mathrm{h}^{2}$

Donald Albin · Accepted Answer

acceleration is a change in speed over a change in time. So if the car goes from 0 to 100 kilometers per hour, that means the change in speed is 100 kilometers per hour and the change in time is two seconds. Um, well, first of all, I do need to convict convert units. And so, um, I see that it says per hour and there are 3600 seconds in an hour. So through 3600 seconds in one hour, the our unit will cancel out. And so I&#x27;m also going to convert kilometers, um, kilometers air in the numerator. So there&#x27;s 1000 meters in one kilometer. Now the kilometers will cancel out. So using a calculator 1000 times, 100 divided by two, divided by 3600 gives me about 14 meters per second squared. And that is be

Averell Hause · Answer

So here the average acceleration is equally to the change in the velocity. With respect to time, it comes to arrest. So the change in the velocity is negative. 40 kilometers. Could Alice and it is brought to rest in six seconds. This would be multiplied by, uh, another one hour for every 3600 seconds. And this is giving us than negative. 24,000 come on meters per hour squared. And so it would be magnitude of the acceleration. We&#x27;re rather the average acceleration is equaling 2 24,000 kilometers per hour squared. And this would then be See, that is the end of the solution. Thank you for watching.

Donald Albin · Answer

in part, a acceleration is the change in velocity over the amount of time. The change in velocity is, um, 0 to 100 kilometers per hour and the change in time is four seconds. Now there are 3000 600 Excited when I change that 3600 seconds in an hour, hours will cancel out and there are 1000 meters in a kilometer. So I&#x27;m going to put this into a calculator. 100 100,000 divided by four and 3600 6.9, um, meters per second. Be if it stopped in five seconds with the same thing. What would have its acceleration be? Well, its acceleration would be negative 100 kilometers per hour over five seconds. So we have to divide by the same 3600 and multiply by the same 1000. And so put that into a calculator. You&#x27;d be negative 5.6 meters per second. See? Yeah. If the mass of the car is 1200 kilograms than what is the Net force on the car? No, the force is the mass times acceleration. So when it&#x27;s stopping which I guess this is what it&#x27;s asking when it&#x27;s when it&#x27;s stopping. Then I have to take the acceleration, which is negative 5.6 times 1200. And that gives me negative 6700 Newtons de what applies the push that accelerates the car? Um, that would be the engine through gears and pistons and that sort of stuff that provides ah and axles that rotates the wheels that pushes against the friction on the road that makes the car go forward.

Kara Merfeld · Answer

right. So, amigo, acceleration is basically how fast something speed changes. So the equation for that is acceleration is the change in velocity over a change in time. And basically, we just have to plug in the things that we know. So this is Ah, the ending velocity or the velocity of time too minus starting velocity or the velocity of time. One divided by how much time that takes. So he said it was 50 a za smiles or kilometers kilometers 50 um, kilometers per hour. 00 Um oh, uh, minus 40 kilometers per hour. It happens in 10 seconds. Okay, so basically, we have 50 minus forties, 10 kilometers per hour per 10 seconds. Sophie, subtract all that out. We have our first RV. It&#x27;s attract 44 50 in the dry, but 10 we&#x27;re left with one kilometer Kurt per hour per second. If we were to put this in more standard units, we could do some dimensional. Alice is to put this in either kilometers per hour squared or kilometers per second squared. Oh, and I guess we should probably do that. So in order to do that. So this this here what? We have is a perfectly correct answer, but we could make it more conventional by changing some units around. So we can either change the seconds in powers or the hours into seconds. And when we do, that is say, okay, we multiply it by, um, Roy, I totally didn&#x27;t mean to make that line right there. We can multiply it by, um, the fact that every hour has 3000 600 seconds per one. Our what we&#x27;re doing, we multiply this number, we can do that. And the reason we can do that is because 3600 seconds is equal to one hour. So we&#x27;re really just multiplying by one. And then we have here. You have a cancellation. You can see that this seconds on top. Cancel It cancels with this seconds on bottom, and we can multiply that out. And this is then, um, 36 100 uh, kilometers per hour per hour. Work per hour. No. Started me to write that. Cross you there or per hour. Squirt

Shital Rijal · Answer

Okay, So the question is asking, what is the acceleration of a car that moves at the student velocity off 100 times per hour? So for how many signals? 100 seconds. Assertion is actually the chains in velocity with respect to time. Right. So in this in not even one second even in power in 100 seconds, there is no chance Adversity in this case here. Indeed he is. Zero right. This implies that there is no change in velocity, so exercise is also equal to zero. My So this is access. And so the Russian wants us to expend this answer. So we can&#x27;t just say that if velocity is constant, the velocity is gone. Standard time with giant two, there is neighbor all Mom, zero acceleration. Okay, so this ends the solution to the school.

Ernest Castorena · Answer

So this time they tell us a car is undergoing celebration. So our acceleration is const. And after four seconds, it is accelerated from 30 miles an hour into 50. So do U minus three report. That&#x27;s just 20/4, which is just five sellers. Acceleration will be increasing by five MPH every second. Let&#x27;s see. So they want to know how much the car has traveled during those three seconds. Well, we know that our velocity, let&#x27;s see, is equal. Teoh starting at 30 and adding five every additional second. So we&#x27;re gonna need to take the position function, and we can take the position at the last second. Subtract the position that sex Teoh what we want. Well, let&#x27;s see the anti derivative. This is fine. He squared over two plus 30 plus some another. See? Okay, whenever we want to know the difference in positions as a sorry 19 seconds. So when we do s for attract s zero will be subtracting this unknown constant from itself. So it&#x27;s gonna cancel out. It&#x27;s irrelevant to us here, So let&#x27;s just plug in for and we&#x27;ll get let&#x27;s see. Five time 16 over to laws 30 times for the track bull zero plus zero. So let&#x27;s complete this. This isn&#x27;t AIDS, so we have 40 plus 1 20 1 60 You can assume that they&#x27;ve traveled the 1 60 miles.

Problem

Copernicus and Kepler engaged in what is called e…

Problem 25 Easy Difficulty

Answer

b

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Laura Kay, Stacy Palen, Brad Smith21st Century Astronomy

Laura Kay, Stacy Palen, Brad Smith

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