A solid uniform disc rolls down a fixed incline without slipping with centre-of-mass acceleration a. What is the friction force exerted by the plane on the disc?
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A solid uniform disc rolls down a fixed incline without slipping with centre-of-mass acceleration a. What is the friction force exerted by the plane on the disc?

G1 Physics · Accepted Answer

For a solid disc rolling down an incline, mg sinθ-f=ma and fR=Iα with I=½mR² and a=αR. Therefore f=½ma. Thus the friction magnitude is ma/2, which corresponds to option C.