A 2kg block on a flat horizontal surface is pulled with a force of 15 N directed 10 degrees above the horizontal. It is found to accelerate at 2m/s^2. Find the coefficient of kinetic friction at the interface?
x: ma=F•cosα-F(fr),
y: 0= - mg+F•sinα +N => N= mg+F•sinα,
ma=F•cosα-μ•N = F•cosα – μ(mg+F•sinα),
μ =(F•cosα – ma)/ (mg+F•sinα).