You carry a 7.0 kg bag of groceries above the ground at constant velocity across a room. How much work do you do on the bag in the process (The force you apply is vertically straight up.)?

Zero.

Explanation:

As it has been said in the question that bag is carried horizontally at constant velocity by lifting  it with an upward force.

So, according to the question the angle between the force and displacement here is 90°.

According to the definition,

Work is the dot product of the force applied to the object and the displacement produced in the object.

So,

Work = = θ

Since the angle is 90°, the value of cosθ in the above equation will be zero and thus the value of net work done will also be zero.

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.