Question 3
which of the following isotopes is not commonly used for dating objects?
a)carbon-14
b)phosphorus-32
c)potassium-40
d)rubidium-87

Among all the given options Phosphorous-32 is not used for dating of objects.

B)phosphorus-32

Explanation:

In this question carbon-14 is the radioactive isotope used in carbon dating process which is  employed  to date the age of remains of organisms. Potassium-40 isotope is used in potassium-argon dating  which is generally used to determine the age of old rocks.

Rubidium-87 is used in rubidium-strontium dating method. In this method rubidium-87  converts into strontium-87 by undergoing beta decay. Age of igneous and metamorphic rocks can be determined using this method.

massxgravity x heght=weightxheight= pe

4900=490xh

h=10

c) up is the direction the magnetic force is acting on the charge.