an object 5 cm in size is placed at 30 cm in front of a concave mirror of focal length 45 CM at what distance from the mirror should a screen be placed in order to obtain a shop image find the magnification size and nature of the image​

Two masses are connected by a rope that hangs over a pulley as shown below. the pulley is a uniform cylinder of radius 푅=0.381meters and mass 푀=3.1푘푔. initially 푚"is on the ground and 푚#rests 2.5 meters above the ground. if the system is released, use conservation of energy to determine the speed of 푚#just before it strikes the ground. assume the pulley bearing is frictionless.