You make a lawn roller out of a \(125-\mathrm{kg}\) solid cylinder, set to rotate about a central axle. You rig up handles on either side of the axle so that you and a friend can pull on the handles horizontally to pull the roller in a direction perpendicular to its rotation axis (Figure P12.101).

(a) If each of you pulls with a horizontal force of \(500 \mathrm{~N}\), what is the magnitude \(a\) of the roller's acceleration?

(b) What is the minimum coefficient of static friction necessary to keep the roller from slipping?

Data from Figure P12.101