alayn h uderstands the half life of a certain substance is 90days. how long would it take for 80lbs of her substance to be reduced to 20lbs

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

Suppose that a mass of 2 kg is attached a spring whose spring constant is 50. the system is damped such that b = 12 . the mass is set in motion with an initial velocity of -8 m/s at a position 0 meters from equilibrium. set up and solve a differential equation that models this motion. write your solution in the form a cos ( ω t − α ) where α is a positive number. use your solution to fill in the information below: what is the amplitude of the motion? what is the value of ω ? what is the phase shift?

The inner planets or call terrestrial because they