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Physics 211, Quiz 5

Question 1:

Michael Jordon jumps 4 feet upwards (1 foot = 0.305 meter). How long does it take him to fall from the peak of his leap back to the ground?

  Answer:   4 feet = 1.22 meters.

            We know

                 displacement  (x - xo)  =  -1.22 m
                 initial velocity  vo    =   0 m/s
                 acceleration      a     =  -9.8 m/s^2

            Use the kinematic equation

                                                                       2
                     (x - xo)   =  vo * (t - to)  +  0.5 * a * (t - to)

                                                                          2
                       -1.22 m  =     0           -   4.9 m/s^2 * (t - to)


            Solve for time
                                          -1.22 m
                      (t - to)  = sqrt( ----------- )
                                         -4.9 m/s^2

                                =  0.5 s 

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