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Physics 211, Quiz 16

Question 1: Joe has a mass m = 60 kg. He enters "The Cyclone," a carnival ride in which a cylindrical room of diameter D = 6 m spins around its axis. Joe stands against the wall as the room stars to spin. It speeds up until it makes one revolution in T = 2 sec.

Joe feels the wall pressing against his back. How strong is this normal force? 

  Answer: The normal force provides the push to keep Joe moving in
          uniform circular motion.  It thus provides the centripetal
          force
                            m v^2
                      F =  ------
                             R

          Here, room has radius R = 3 m, and circumference 
          C = 2 pi R = 18.8 meters.  The room makes on revolution
          in T = 2 seconds, and Joe spins with speed

                              C       18.8 m
                      v  =  -----  =  ------  =  9.4 m/s
                              T        2 s


          Therefore, the centripetal force is

                            m v^2      (60 kg) * (9.4 m/s)^2
                      F =  ------  =  -----------------------
                             R                3 m

                        = 1770 N

Creative Commons License Copyright © Michael Richmond. This work is licensed under a Creative Commons License.