The loss of prestress due to elastic shortening of concrete is least in

The maximum bending stress induced in a steel wire of modulus of elasticity $$200$$ $$kN/m{m^2}$$ and diameter $$1$$ $$mm$$ when wound on a drum of diameter $$1$$ $$m$$ is approximately equal to

In a real beam, at an end, the boundary condition of zero slope and zero vertical displacement exists. In the corresponding conjugate beam, the boundary conditions at this end will be:

A cantilever beam of span, $$'L'$$ is subjected to a downward load of $$800$$ $$kN$$ uniformly distributed over its length and a concentrated upward load $$P$$ at its free end. For vertical displacement to be zero at the free end, the value of $$P$$ is: