How many days will it take for one half of the original amount of a radioactive substance to decay if the half-life is 30 days?

a. 3 days

b. 15 days

c. 30 days

d. 60 days

A crate falls from an airplane flying horizontally at an altitude of 2,000 m. Neglecting air drag, how long will the crate take to strike the ground?

How do you calculate the total resistance of a series circuit

Circular motion occurs on earth true or false

What are the responsibilities of the moderator in a discussion?

Which statement is true about the scientific method? A. It follows one prescribed sequence of steps. B. It begins and ends with an experiment. C. It is used only in Earth and space science. D. It can be cyclic.

What are some ways the oceanic crust and the continental crust are alike?

Why is gangue sometimes reprocessed.

4.7 cm. The tube is sealed at one end and loaded with lead shot to give it a total mass of M = 130 g. The tube floats in water (of density 1 g/cm3) in vertical position, loaded end down.

Why is it incorrect to say that vascular tissue, gametophytes, and fronds are all found mosses

Can the validity of a model be limited, or must it be universally valid? How does this compare to the required validity of a theory or a law?