The half-life for an 80-gram sample of an unknown radioactive element is 5 days. how much of the unknown radioactive element remains after 10 days have passed? A.20g
B.40g
C70g
d80g

Which radioisotope is used in dating geological formations?

What efficiency of a car's engine when heat input is 200,000 joules and waste heat is 150,000 joules? a. 75% b. 35% c. 25% d. 85%

Arope has one end tied to a vertical support. you hold the other end so that the rope is horizontal. if you move the end of the rope back and forth with a frequency of 4 hz, the transverse wave you produce has a wavelength of 0.5 m. what is the speed of the wave in the rope?