.Why does it take double the applied force to move a mass double the size? Explain this in terms of inertia,

Which statements best describe medical uses for radioactive isotopes? check all that apply. radioactive isotopes are used to detect medical problems. high-energy gamma rays are injected into the body. radioactive isotopes are used to treat some diseases. radiation is used to kill cancer cells. radioactive isotopes are directed at tumors from outside the body.