In an ideal wheel an axle system, R stand for the radius of the wheel and r is the radius of the axle. the mechanical advantage is

Answer Details

The question is asking about the mechanical advantage in an ideal wheel and axle system where R is the radius of the wheel and r is the radius of the axle. The mechanical advantage in this system is given by the ratio of the radius of the wheel to the radius of the axle, which is R/r. Therefore, the answer is (D) R/r.