If the half-life of iodine-131 is 8 days, how old is a sample if only 1/8 of the original amount remains? write 2-3 sentences explaining your answer.

Sound waves are mechanical waves in which the particles in the medium vibrate ina direction parrallel to the direction of energy transport. what is another name of the type of wave that transfers energy in this way?

Apulley with a mechanical advantage of 5 will require you to pull times the amount of rope. a. 1/5 b. 5 c. 10 d. 15

Iron reacts with sulfur to form iron sulfide. if 60 grams of iron reacts with sulfur to produce 90 grams of iron sulfide, how much sulfur has been used in the chemical reaction?