Noah is loading the ark and the last animal on board is a stubborn 1500-kg elephant who refuses to budge. Noah and his family pull the elephant at a constant speed up the 10° incline with a force of 10,000 N. What is the coefficient of sliding friction between the elephant and the loading platform?

Respuesta :

The coefficient of sliding friction is 0.514

Explanation:

We start by writing the equations of motion of the elephant along the two directions, parallel and perpendicular, to the incline.

Along the parallel direction we have:

[tex]F- mg sin \theta - \mu_k R = ma[/tex] (1)

where :

F = 10,000 N is the force applied by Noah

[tex]mg sin \theta[/tex] is the component of the weight parallel to the incline, where:

m is the mass

g = 9.8 m/s^2 the acceleration of gravity

[tex]\theta=10^{\circ}[/tex]  is the angle of incline

[tex]\mu_k R[/tex] is the force of friction, where:

[tex]\mu_k[/tex] is the coefficient of friction

R is the normal reaction  

and a is the acceleration

Perpendicular direction:

[tex]R-mg cos \theta =0[/tex] (2)

where [tex]mg cos \theta[/tex] is the component of the weight perpendicular to the incline

From (2) we find

[tex]R=mg cos \theta[/tex]

And substituting into (1)

[tex]F-mg sin \theta - \mu_k mg cos \theta = ma[/tex]

We know that the elephant moves at constant speed, so the acceleration is zero:

a = 0

So the equation becomes

[tex]F-mg sin \theta - \mu_k mg cos \theta=0[/tex]

And we can re-arrange it to find the coefficient of friction:

[tex]F-mg sin \theta - \mu_k mg cos \theta=0\\\mu_k = \frac{F-m g sin \theta}{mg cos \theta}=\frac{10000-(1500)(9.8)(sin 10)}{(1500)(9.8)(cos 10)}=0.514[/tex]

Learn more about friction and inclined planes:

brainly.com/question/5884009

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