not my best on a physics test... feeling down

mikau · 2008-04-10 10:10:12

so this morning I took the 3rd of 4 tests for my physics course. The test covered momentum and collisions, rotation, torque and angular momentum, equilibrium, and gravity. 5 chapters we covered since the last test, and there was 5 sets of questions each worth 20 points.

So I did perfectly fine on the first two, but the third puzzled me. We were given a car, that could accelerate to 45 km/h in 10 seconds. We had to find the kinetic energy of each wheel of known mass and unknown radius. I could not remember the formula for kinetic energy of a rolling object, and our teacher only lets us bring a small handful of formulas with us. This one I didn't have.

So I spent about 15 minutes trying to derive the radius of the wheel based on how fast it accelerated, but i didn't seem to have enough values. So I decided to quickly finish up the other problems, which looked easy, and just concentrate on that for the remainder. So I moved quickly through the last few problems, and came back with about 20 minutes left on the clock. I thought about trying to determine the torque on each wheel based on acceleration, but that got nowhere. Finally, I remembered the formula was something like 1/2 (wr)^2, and wr could be replaced with v. So I finished with about 5 minutes left on the clock, and handed it in. The teacher looked it over, and pointed to the rotational energy formula i used, saying it was off by a factor of 2, and then he showed that I forgot to include the force due to gravity on a balancing beam in the equilibrium problem.

I asked him about what I would get for the exam, and he said probably 80%.

80%? One of my formulas was off by 1/2, and made one other mistake. Is that really worth only 80?

I feel like I'm getting killed by how few formulas we're allowed to bring. Honestly, if I had that one with me, I would have gotten that right, and had more time to look at the other problems, and do them slower and more carefully.

Thus far I got 100 on the first test, 88 on the second, and now it seems this one will be 80 at best. I'm not liking the pattern I'm seeing here.

LuisRodg · 2008-04-10 10:45:19

My story is sadder...

First test on Physics I got a 94. Good enough.

My second test was on the SAME stuff as you, torque, collisions, angular etc. I got a 26 on it... I just didnt understand the stuff to be honest. I just dropped the class.

math > physics

mikau · 2008-04-10 10:58:10

Ha!

i find a lot of stuff in physics to be...weakly defined. At least the way its presented in my book.

Thing is though, i knew what i was doing in every problem. I just made a stupid mistake in one, and forgot the formula in another.

Makes me furious.

SvenBee · 2008-04-10 12:50:52

Well I have some test blues to submit as well...

Took the practice AP CalcAP exam as a graded assignment in Calc today. It's 1/3 of our grade and the system at my school (High school FYI) is that if you gat an A in the 3rd and 4th nine week period you opt out of your final exam. Anyways, 9 days of school left and I'm psyched, then I get to 6th period and look at this test. o.O <-- is honestly how I felt, I knew everything fairly well, except for trig (which vacated my mind when I first tried to recall it). To make a long story short I have to take the calc exam now. But on the up side, 9 days of school left, then graduation, then moving to college.

mikau · 2008-04-10 12:59:58

Well good thing you got another test yet to come. Reminds me of my situation. I do still have a final exam which is worth 25% of our total grade for the course. So thats going to make or break my grade for the course.

LuisRodg · 2008-04-10 13:02:47

Hehe.

I got a 5 in AP Calc ....

You will love college way more than High School. Im having a great time.

I just HATED the fact you were treated as a kid when you were 18 years old. Senior year when I wanted to go home because I just felt like going. They had to call my mom every single time and make sure she says its ok...wtf?

I have an awesome mom who trusts me a lot. She says she remembers when she was in school and some days she felt like not going etc. Ever since 9th grade she told me any day i didnt feel like going to school to just tell her and she wouldnt mind since she knew I was smart and responsible and would balance it out. And thats exactly what i did. I was no idiot. Like, I knew if I was absent it was just worst for me but it was good to know that one of those days when you just feel like c-r-a-p or you KNOW that your aint doing s-h-i-t in school, that I could stay home and my mom wouldnt mind. I love my mom

Anyways, college is awesome. You will love it.

Last edited by LuisRodg (2008-04-10 13:05:18)

SvenBee · 2008-04-10 14:06:37

I have the same kind of dad woot. And college is going to be fun, I'm moving from Louisiana to Mass. So LONG ways away. I'll be 18 in October so I'll be 17 when I start school. And on another positive note I'm getting my next tattoo in a week. woot.

Math Is Fun Forum

#1 2008-04-10 10:10:12

not my best on a physics test... feeling down

#2 2008-04-10 10:45:19

Re: not my best on a physics test... feeling down

#3 2008-04-10 10:58:10

Re: not my best on a physics test... feeling down

#4 2008-04-10 12:50:52

Re: not my best on a physics test... feeling down

#5 2008-04-10 12:59:58

Re: not my best on a physics test... feeling down

#6 2008-04-10 13:02:47

Re: not my best on a physics test... feeling down

#7 2008-04-10 14:06:37

Re: not my best on a physics test... feeling down

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