For approximately how long has life existed on the surface of the earth visible without a microscope

Sr-90 has a half-life of T1/2 = 2.85 a (years). How much Sr-90 will remain in a 5.00 g sample after 5.00 a? Show all of your work. (2 marks)

Describe the rise and fall of a thrown basketball by using the concepts o kinetic energy and potential energy

A block has acceleration a when pulled by a string. if two identical blocks are glued together and pulled with twice the original force, what will their acceleration be?

Which type of fault involves compression? A. normal B. reverse C. transform D. normal and reverse

Two conducting spheres, one having twice the diameter of the other, are separated by a distance that is large compared to their diameters. The smaller sphere has charge q and the larger sphere is uncharged.

In order for an object to conserve it's total mechanical energy it is absolutely necessary that?

Your body is presently converting chemical potential energy from food into thermal energy at a rate of about 100 J/s, or 100 W. If heat were flowing out of you at a rate of about 200 W, would your body temperature go up or down?

Which energy depends the arbitrarily assigned zero level

What is a transverse wave

Object moving at a constant velocity will always have a