Physics
posted by Angela on .
A car travels at a constant speed around a circular track whose radius is 2.9 km. The car goes once around the track in 380 s. What is the magnitude of the centripetal acceleration of the car?

its velocity is 2PIr/380
a=v^2/r 
thats wrong, thanks anyways bobpursley

actually, it is right. Did you change radius to meters?
Let me see your work. 
ok so v= 2(pi)(2900)/ (380)
v=47.95 m/s
a=v^2/r= (47.95)^2/(2900)= .792828... and I checked my answer and it was wrong 
IM SO SORRY! it was right! Thanks again! I need help with one more question can u help me?

well, I would mark it wrong because of significant digits. You should have no more than two significant digits, I hope you know why.
a= .79m/s^2 
Yes thank you. I got it can u help me with this one?
There is a clever kitchen gadget for drying lettuce leaves after you wash them. It consists of a cylindrical container mounted so that it can be rotated about its axis by turning a hand crank. The outer wall of the cylinder is perforated with small holes. You put the wet leaves in the container and turn the crank to spin off the water. The radius of the container is 12 cm. When the cylinder is rotating at 2.3 revolutions per second, what is the magnitude of the centripetal acceleration at the outer wall?