March 20,Centripetal Force

Hi!
Today's Class

We went over the "practice problem" pages 152-153 questions 13-16


Ms.K gave us the CENTRIPETAL FORCE worksheet (it is due on Tuesday)


Answers:(problems 13-16)

13. It takes a 615 kg racing car 14.3 s to travel at a uniform speed around a circular racetrack
of 50.0 m radius.
a.What is the acceleration of the car?




b. What average force must the track exert on the tires to produce this acceleration?



14. An athlete whirls a 7.00kg hammer tied to the end of a 1.3 m chain in a horizontal circle .The hammer
moves at the rate of 1.0 r/s.


a.What is the centripetal acceleration of the hammer?




b.What is the tension in the chain?




15. Sue whirls a yo-yo in a horizontal circle.The yo-yo has a mass of 0.20kg and is attached to a string 0.80
long.
a.If the yo-yo makes 1.0 complete revolution each second ,what force does the string exert.



b. If Sue increases the speed of the yo-yo to 2.0 revolutions per second ,What force does the
string exert on it?



16. A coin is placed on a stereo record revolving at 33 1/3 revolution per minute.

a.In what direction is the acceleration of the coin ,if any?
Ans. Inward

b.Find the acceleration of the coin if any ,when it is placed 5.0,10.0,15.0 cm from the center of
of the record.
Ans. 5.0 cm-------0.609 m/s2
10.0 cm -----1.218 m/s2
15.0 cm----- 1 .28 m/s2


c.What force accelerate the coin?

Ans.Friction


d.At which of the three radii listed in b would the coin be most likely to fly?

Ans. 15.0 cm

So, thats all for today's class.....(=*.*=)....the next scribe will be ramina..:>