Is there enough grip to roll?

A uniform solid cylinder is released from rest on a fixed incline with tanθ=0.75. Its central inertia is I=mr²/2. There are no applied forces other than gravity and contact.

What is the minimum coefficient of static friction for pure rolling?

Organize the givens & assumptions

I/(mr²)=1/2
tanθ=0.75

Rigid cylinder and plane; no rolling resistance; gravity uniform; test the no-slip model before using its acceleration.

A $0.75$
B $0.50$
C $0.25$
D $0.125$

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