Answer:
Explanation:
Given
mass of box [tex]m=80 kg[/tex]
coefficient of kinetic friction [tex]\mu _k=0.15[/tex]
coefficient of Static friction [tex]\mu _s=0.30[/tex]
cart is moving with constant velocity therefore Net Force is zero
Since there is no net acceleration therefore friction force will be zero
mathematically
[tex]f_r=ma[/tex]
where [tex]f_r=frictional\ Force[/tex]
[tex]a=acceleration[/tex]
[tex]a=0[/tex]
[tex]f_r=0[/tex]