A cylinder of mass \( m \) and radius \( r \) rests on two supports of the same height (Fig. 18)...

A cylinder of mass \( m \) and radius \( r \) rests on two supports of the same height (Fig. 18). One support is stationary, while the other slides from under the cylinder at a velocity \( v \).
Determine the force of normal pressure \( N \) exerted by the cylinder on the stationary support at the moment when the distance between points \( A \) and \( B \) of the supports is \( A B=r \sqrt{2} \), assuming that the supports
Fig. 18
were very close to each other at the initial instant. The friction between the cylinder and the supports should be neglected.