Definition: This law states that, in any process, energy is neither created nor destroyed. It can only be converted from one form to another.

What is the measurement of how fast an object moves relative to a reference point?

The energy released by a nuclear fusion reaction is produced when

The radioactive isotope of lead, pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.3 hours. if 1 gram of this isotope is present initially, how long will it take for 80% of the lead to decay? (round your answer to two decimal places.)