A15 m ladder whose weight is 312 n is placed against a smooth vertical wall. a person whose weight is 579 n stands on the ladder a distance 2.4 m up the ladder. the foot of the ladder rests on the floor 6.45 m from the wall.
a) calculate the force exerted by the wall. answer in units of n.
b) calculate the normal force exerted by the floor on the ladder. answer in units of n.

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up