Examples of physical properties include: color, shape, size, density, melting point, and boiling point.
Answer:
The mass of the boulder remains constant, while its weight decreases with respect to the value of gravitational force on the moon.
Explanation:
The mass of the boulder = 15 kg
On the earth, its mass remains 15 kg. But its weight is;
weight = m x g
= 15 x 9.8
= 147 N
The boulder's weight on the earth is 147 N.
When transferred to the moon, the mass remains constant i.e 15 kg. But its weight decreases due to a change in the value of acceleration due to gravity on the moon. Thus, the boulder becomes lighter in weight.
Via half-life equation we have:

Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:

There is 6.25 grams left of Ra-229 after 12 minutes.
Fragments and gamma<span> rays</span>
A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled. The independent variable is the one that is changed by the scientist.