Acceleration & velocity

[richardmarco]

Today's mcat question (here) threw me off big-time. How I felt:

Anyone else get thrown off?

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[SaintJude]

Yeah the question is playing on the definition of uniform circular motion: An object moving in a circle of radius r with constant speed v is accelerating.

The velocity, is a vector quantity, is changing (only in its directions). Since direction of velocity is changing, there must be an acceleration (in the direction of the net force--which is towards the center)

I think this is a good question, because in the anxiety of MCAT testing, a lot of people could forget this, so I jut like to stick in a mantra:
Uniform Circulation Motion: There is an acceleration, (expletive)... Seriously, that's what I remember.

 

[richardmarco]

I think this is a good question, because in the anxiety of MCAT testing, a lot of people could forget this, so I jut like to stick in a mantra:
Uniform Circulation Motion: There is an acceleration, (expletive)... Seriously, that's what I remember.

Haha, I'll try to remember that! Thanks.

 

[MedPR]

No, but only because I've fallen for this trap about a billion times in TBR/NOVA/EK 1001.

 

[Class1P]

Always remember that if an object is changing direction during it's motion, it is accelerating.

Velocity is a vector so if you change just the direction of the arrow, you are creating an acceleration or a "change in velocity" regardless of the scalar quanitity.

for that question you just use the equation for rotational acceleration a = (v^2)/r

 

[silverice]

No, but only because I've fallen for this trap about a billion times in TBR/NOVA/EK 1001.

I felt for the trap as well. LOL! gotta love these tricky MCAT questions!