physics concept quesiton

[Eeezee]

I felt like bumping this because there's just so much laughter

 

[notfred]

Based on the question, it could be anything. I say it's 35,000 astronomical units/year^2

The question says nothing about being near earth, or what height is relative to.

 

[NaOH]

LOL Titan got ****** owned....

 

[timosyy]

FWIW, this thread made me laugh.

Gravity is your friend. And everything has a constant -9.8m/s/s acceleration downwards acting on it. Learn to love it? It makes me happy when i'm writing out equations that "g" is always constant.

 

[pray4mojo]

lol at this thread.

its great how people pick apart the question without applying a little common sense. its from a physics exam most likely from high school. you all know that its on earth and neglects any frictional forces and such so the answer is 9.81.

 

[zanieladie]

Oh brother...up to 4 pages in this thread!

 

[Merlyn3D]

Originally posted by: Fenixgoon

Originally posted by: ledjani
Well I believe the answer is 0. The derivative of the velocity is acceleration. Thus whenever the graph of the velocity reaches its max, the derivative is 0. Thus the acceleration is 0. Because it is at rest acceleration wise, it has reached the top, and it isn't going up or down anymore.

WRONG. please retake physics/ calc

The question is somewhat unclear. It should say "assuming the particle has no other force acting on it" or something. It's kinda of unclear.

Assuming the only force is gravity though, the answer is 9.81m/s. It's not 0. Why? lenjani is right, derivative of velocity is acceleration, but velocity doesn't reach a so called "max", and that's where you make your mistake. Here's the connection you're missing. Derivative of position vs time gives you velocity. The position vs time graph is parabolic and upside down (think -x^2) thus it will have a max height.

The derivative of such a graph will intuitively be linear (think a straight line) with a negative slope and an x-intercept at the time where the position is a max. This is your velocity.

Finally, take the derivative of that velocity (a straight line), and you will get a constant. In the case of gravity being the only force at work, it's -9.81. Given that the question wants the value of the magnitude, you treat that acceleration as a vector, and take it's magnitude, which is always positive, and that is 9.81.

 

[Brainonska511]

Why does this thread keep coming back up?

 

[Wnh5001]

😵, they love gravity that much, the test was on kinematics in 1d, 2d, vectors, and forces. Test taken from a college course, Physics: Mechanics and i believe the answer is 9.8m/s2. =/ i scored a 55 on that test and the next test >_<.. luckily everyone also bombed the 2nd test so 14 point curve!!! 😀. im still boarderline to passing at a 73. >_<

 

[Schfifty Five]

LOL, forgot about this thread.

But yes, the question should have mentioned "NO OTHER FORCES ACTING UPON IT" except gravity and given the answers, it's pretty clear that only gravity was affecting it.

 

[timosyy]

Upon re-reading OP, yeah, not the best question.

That question is typically worded more along the lines of "Soandso tosses a ball into the air, what is the acceleration at its highest point/peak?". /shrug

 

[SaturnX]

Originally posted by: Beige
this just shows that Physics kicks Chemistry's butt any day.
Physics <3 FTW

Actually I think this shows that:

Basic Physics Concepts > Majority of ATOT

The answer is 9.81 m/s/s.

/thread

 

[bhanson]

Originally posted by: Wnh5001
a particle reaches it max height t= 2 seconds, what is the magnitude of its acceleration?

|hint|- the t=2 seconds doesnt mean anything =S, choose wisely,

a)19.6
b)9.81
c)0
d)-9.81

e) None of the above because there are no units on the numbers!

(Yes I've taken Physics and know what you *mean*, but that's not what you said.)

9.81 feet per second 😉

 

[Born2bwire]

Originally posted by: SaturnX

Originally posted by: Beige
this just shows that Physics kicks Chemistry's butt any day.
Physics <3 FTW

Actually I think this shows that:

Basic Physics Concepts > Majority of ATOT

The answer is 9.81 m/s/s.

/thread
QFT.
This whole thing is just freakin hilarious.

 

[RapidSnail]

lol @ thread...is it still safe to assume that 2+2=4?