Ahailstone traveling with a velocity of 43 meters/second comes to a virtual stop 0.28 seconds after hitting water. what is the magnitude of its acceleration in the water?
a. 12 meters/second2
b. 1.5 × 102 meters/second2
c. 78.6 meters/second2
d. 6.5 × 10-3 meters/second2

Magnitude of acceleration = (change in speed) / (time for the change) .

Change in speed = (ending speed) - (starting speed)

                            =       zero            - (43 m/s)

                            =          -43 m/s .

Magnitude of acceleration = (-43 m/sec) / (0.28 sec)

                                          =  (-43 / 0.28)  (m/sec) / sec

                                          =        153.57...  m/s²

                                          =        1.5...  x 10²  m/s²  .