75) A ladder of weight ′w′ rests against a smooth vertical wall, and rests on rough horizontal ground, the coefficient of friction between the ladder and the ground being 1/4. The maximum angle of inclination of the ladder to the vertical, if a man of weight ′w′ is to walk to the top of it safely, is tan′1 x, where x is

76) If a body is lying on a plane whose inclination with the horizontal is less than the angle of friction, then i) a force is required to move the body upwards ii) a force is required to move the body downward iii) the body will not be in equilibrium The correct answer is

77) Intrinisic equation of catenary is given by[where C is some constant.]

78) The shape of a suspended cable for a uniformly distributed load over it is

79) Cartesian form of the equation of catenary is