A box is sliding on a rough patch of ice, and the only horizontal force acting on it is friction. You observe that it slides to a stop in 600 seconds over a distance of 20 meters. What magnitude is coefficient of static friction between the box and the ice?

Respuesta :

Answer:

The coefficient of static friction is 1.13x10⁻⁵.      

Explanation:

We can find the coefficient of static friction as follows:

[tex] -F_{\mu} = ma [/tex]

[tex] -\mu N = ma [/tex]

[tex] -\mu mg = ma [/tex]

[tex] \mu = -\frac{a}{g} [/tex]    (1)

Where:

[tex] F_{\mu}[/tex]: is the friction force

m: is the mass of the box

a: is the acceleration

g: is the gravity = 9.81 m/s²

First, we need to calculate the acceleration:

[tex] v_{f} = v_{0} + at [/tex]      (2)

Where:

[tex] v_{f}[/tex] is the final speed of the box = 0

[tex] v_{0}[/tex] is the initial speed of the box

t is the time = 600 s

[tex] v_{f}^{2} = v_{0}^{2} + 2aX [/tex]    (3)

Where:

X: is the distance traveled by the box = 20 m

By solving equation (2) for [tex]v_{0}[/tex] and by entering into equation (3) we have:

[tex] 0 = (-at)^{2} + 2aX [/tex]

[tex] a = \frac{-2X}{t^{2}} = \frac{-2*20 m}{(600 s)^{2}} = -1.11 \cdot 10^{-4} m/s^{2} [/tex]

Now, we can calculate the coefficient of static friction by entering the above value into equation (1) :

[tex] \mu = -\frac{a}{g} = -\frac{-1.11 \cdot 10^{-4} m/s^{2}}{9.81 m/s^{2}} = 1.13 \cdot 10^{-5} [/tex]

Therefore, the coefficient of static friction is 1.13x10⁻⁵.              

I hope it helps you!