10. which one of the following accurately describes the force of gravity?
a. the gravity acceleration is in the same direction as the force of gravity, and thus toward the center of the earth.
b. the force of gravity is slightly lower at the bottom of a mountain than it is at the top.
c. the gravity acceleration has no effect on a body moving in directly the opposite direction of the force of gravity.
d. the gravity acceleration is in the same direction as the force of gravity, and thus away from the center of the earth.

Acyclotron is used to produce a beam of high-energy deuterons that then collide with a target to produce radioactive isotopes for a medical procedure. deuterons are nuclei of deuterium, an isotope of hydrogen, consisting of one neutron and one proton, with total mass 3.34×10−27kg. the deuterons exit the cyclotron with a kinetic energy of 6.40 mev .a-what is the speed of the deuterons when they exit? b-if the magnetic field inside the cyclotron is 1.25 t, what is the diameter of the deuterons' largest orbit, just before they exit? c-if the beam current is 350 μa how many deuterons strike the target each second?