A wheel has a constant angular acceleration of 3.5 rad/s2. During a certain 9.0 s interval, it turns through an angle of 220 rad. Assuming that the wheel started from rest, how long had it been in motion before the start of the 9.0 s interval

It had been 2.48 s before the start of the 9.0 s interval

Explanation: Please see the attachments below

2.5 s

Explanation:

We use the equation of motion for rotational motion:

where

Substituting values,

Before the 9.0 s interval, this value is the final angular velocity. The initial angular velocity is 0 rad/s since it started from rest.

We use the equation:

Note that is the value we got earlier and is the initial angular velocity and is equal to 0 rad/s.

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.

the higher the current the higher the mag field around it the higher the influence on the compass