If 1 g of Californium-251 has decayed from a sample that was originally 2 g, how old is the sample?

What is relative velocity? in which condition is relative velocity known by adding the velocity of the first body and that of the second body

Abanked road comer of radius 146 m is to be constructed. if the comer is designed for vehicles moving with a speed of 20.0 m/s, what should the banking angle be, in units of degrees?

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.