What is the half life of a radioactive isotope that decreased to one-fourth its original amount in 100 year

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

According to newton’s law of universal gravitation, which statements are true? as we move to higher altitudes, the force of gravity on us decreases. as we move to higher altitudes, the force of gravity on us increases. as we gain mass, the force of gravity on us decreases. as we gain mass, the force of gravity on us increases. as we move faster, the force of gravity on us increases.

Sunidhi made a study chart about changes in states of matter. which headings best complete the chart?