(serway 9th ed., 9-3) at one instant, a 17.5-kg sled is moving over a horizontal surface of snow at 3.50 m/s. after 8.75 sec has elapsed, the sled stops. use a momentum approach to find the average friction force acting on the sled while it was moving. (ans. 7.00 n)

F = 7 N

Explanation:

given,                                

mass of sled = 17.5 Kg                                    

speed of snow on horizontal surface = 3.5 m/s

time taken to stop = 8.75 s

initial momentum              

  = m U                              

 = 17.5 x 3.5 = 61.25 Kg.m/s

final momentum                        

final velocity = 0 m/s            

final momentum = 0                    

impulse = change in momentum

impulse = force x time    

equating both the formula of impluse    

F x t = 61.25 - 0

F x 8.75 = 61.25            

F = 7 N                                                

Force acting on the moving sled is equal to F = 7 N

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