A hockey puck is sliding across a frozen pond with an initial speed of 9.5 m/s. It comes to rest after sliding a distance of 37.4 m. What is the coefficient of kinetic friction between the puck and the ice

Respuesta :

Answer:

The coefficient of kinetic friction between the puck and the ice is [tex]\mu _{k} =[/tex] 0.12

Explanation:

Given :

Initial speed  [tex]v_{o} = 9.5 \frac{m}{s}[/tex]

Displacement [tex]x = 37.4[/tex] m

From the kinematics equation,

  [tex]v^{2} - v^{2} _{o} = 2ax[/tex]

Where [tex]v^{2} =[/tex] final velocity, in our example it is zero ([tex]v =0[/tex]), [tex]a =[/tex] acceleration.

   [tex]a =- \frac{90.25}{ 2 \times 37.4}[/tex]

   [tex]a =- 1.21 \frac{m}{s^{2} }[/tex]

From the formula of friction,

  [tex]F =- \mu _{k } N[/tex]

Minus sign represent friction is oppose the motion

Where [tex]N = mg[/tex] ( normal reaction force )

 [tex]ma = -\mu _{k} m g[/tex]                                                  ( ∵ [tex]g = 9.8 \frac{m}{s^{2} }[/tex] )

So coefficient of friction,

 [tex]\mu_{k} = \frac{1.21}{9.8}[/tex]

 [tex]\mu_{k} = 0.12[/tex]

Therefore, the coefficient of kinetic friction between the puck and the ice is  [tex]\mu _{k} =[/tex] 0.12 .

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