What is the average velocity of the particle from rest to 15 seconds? A. 1.1 meters/second B. 1.2 meters/second C. 1.3 meters/second D. 1.4 meters/second

D. 1.4 meters/second

Explanation:

To calculate average Velocity, the proportion of the total Displacement or distance traveled to the total time taken during that Displacement is calculated.

Total Displacement from rest(that is 0) to 15 seconds (21, on the graph)

(0, 21)

Total time taken = 15 seconds

Average Velocity = (total Displacement / total time taken)

Average Velocity = (21 - 0) / (15 - 0)

Average Velocity = 21 / 15

Average Velocity = 1.4 meters per second

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.

double the distance = divide strength by 4