If a scientist has 80 g of strontium-90, how many grams remain after 4 half lives?

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

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

Two waves maximally constructively interfere at a point in space. among the options below, select the possible value of their phase difference at that point in space. a. zerob. πc. π/2d. not determinable by the information provided