mass of the chair = 25 kg
Force required to start the motion = 165 N
Force required to maintain the motion = 127 N
part a)
when we applied the force to just start the motion then it is just equal to the limiting friction force
[tex]F_s = F[/tex]
now as we know that
[tex]\mu_s mg = 165[/tex]
[tex]\mu_s * 25 * 9.8 = 165[/tex]
[tex]\mu_s = \frac{165}{25*9.8}[/tex]
[tex]\mu_s = 0.67[/tex]
PART b)
when object has started motion then to maintain its motion we need external force to balance kinetic friction
[tex]F_k = F[/tex]
now as we know that
[tex]\mu_k mg = 127[/tex]
[tex]\mu_k * 25 * 9.8 = 127[/tex]
[tex]\mu_k = \frac{127}{25*9.8}[/tex]
[tex]\mu_k = 0.52[/tex]
