How Does a Salad Spinner Utilize Centripetal Force?

[soccerjayl]

The question is: 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 14 cm. When the cylinder is rotating at 1.8 revolutions per second, what is the magnitude of the centripetal acceleration at the outer wall?

My answer is 3.07 m/s^2, however it is wrong.

What i did: A(c)=(4pi^2 x 0.14 m)/1.8 sec

(1.8 sec)(A(c))=5.527

A(c)=3.07 m/s^2

What did I do wrong?

 

[soccerjayl]

sorry..i figured it out:

just for anyone's curiosity, the solution:

Had to convert period to frequency, or 1.8 to 1/1.8 (5/9).

A(c)=(4pi^2 x 0.14 m)/(5/9)^2

(25/81)A(c)=5.53

A(c)=17.9 m/s^2

 

[wais]

Your calculation for the centripetal acceleration is correct, however it is missing the unit of time in the final answer. The unit for centripetal acceleration is meters per second squared (m/s^2), which means the final answer should be 3.07 m/s^2. So, your calculation is correct, but you just forgot to include the unit in the final answer.