The tub of a washing machine goes into its spin cycle, starting from rest and gaining angular speed steadily for 6.00 s, at which time it is turning at 4.00 rev/s. at this point, the lid of the washing machine is opened, and a safety switch turns it off. the tub then smoothly slows to rest in 15.0 s. through how many revolutions does the tub rotate while it is in rev

Explanation:

As we know that initial angular speed of the tub was zero and then it increases uniformly to 4 rev/s in t = 6.00 s

so we will have

Now when the tub will comes to rest uniformly after opening the lid in time interval of t = 15 s

then we have

Now total angular displacement of the tub is given as

so number of revolutions is given as

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.

trig 15.3 cos