An object with a mass of 6 kg is pushed along a linear path with a kinetic friction coefficient of u_k(x)= 2+cscx . How much work would it take to move the object over #x in [pi/6, (3pi)/4], where x is in meters?

1 Answer
May 8, 2018

The work is =344.57J

Explanation:

"Reminder : "

intcscxdx=ln|(tan(x/2))|+C

The work done is

W=F*d

The frictional force is

F_r=mu_k*N

The coefficient of kinetic friction is mu_k=(2+csc(x))

The normal force is N=mg

The mass of the object is m=6kg

F_r=mu_k*mg

=6*(2+csc(x))g

The work done is

W=6gint_(1/6pi)^(3/4pi)(2+csc(x))dx

=6g*[2x+ln|(tan(x/2))|]_(1/6pi)^(3/4pi)

=6g(3/2pi+ln(tan(3/8pi)))-(1/3pi+ln(tan(1/12pi))

=6g(5.86)

=344.57J