what will be the focal lenght of a combined lens made by contact of two lenses of power +3D and -2D.​

Fill in the blank. the number of each type of element in the compound (other than 1) is represented by a small number to the right of the element symbol.

State one advantage and one disadvantage of using a plane mirrior as a driving mirrior

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n