A hockey player whacks a 162-g puck with her stick, applying a 171-N force that accelerates it to 42.3 m/s. A. If the puck was initially at rest, for how much time did the acceleration last? B. The puck then hits the curved corner boards, which exert a 151-N force on the puck to keep it in its circular path. What’s the radius of the curve?

Given parameters:

Mass of puck = 162g  = 0.162kg (1000g = 1kg)

Force exerted on puck = 171N

Final velocity  = 42.3m/s

Unknown

A.  time of the acceleration

B. radius of the curve?

Solution:

A. time of the acceleration

the initial velocity of the puck = 0m/s

    We know that;

              Force  = mass x acceleration

      Acceleration  =

       Acceleration  =

  So force  = mass x

 Input the parameters and solve for time;

             171 = 0.162 x

             171 =  

                 t =   = 0.04s

The time of acceleration is 0.04s

B. radius of the curve;

      to solve this, we apply the centripetal force formula;

               F  =

  where;

      F is the centripetal force

     m is the mass

      v is the velocity

      r is the radius

               Since the force exerted on the puck is 151;

      input the parameters and solve for r²;

             151 =

               151r  = 0.162 x 42.3²

                r  = 1.92m

The radius of the circular curve is 1.92m

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