If the forces acting upon an object are balanced, then an object must a) be moving. b) be accelerating. c) be beginning to slow down. d) be moving at a constant velocity.

The correct answer to the question is : D) Be moving at a constant velocity.

EXPLANATION:

As per Newton's first laws of motion, every body continues to be  at state of rest or of uniform motion in a straight line unless and until it is compelled by some external unbalanced forces acting on it.

Hence, it is the unbalanced force which changes the state of rest or motion of a body. Balanced force is responsible for keeping the body to be either in static equilibrium or in dynamic equilibrium.

As per the options given in the question, the last one is true for an object under balanced forces.

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

probably not if net force is zero