An elevator ascends from the ground with uniform speed. a time tį later, a boy drops a marble through a hole in the floor. a time t2 after that (i. e. ti +t2 after start) the marble hits the ground. find an expression for the height of the elevator at time ti. (local gravity is g.) what checks can you make?

The height of the elevator at is

Solution:

As per the question:

Let us assume:

The velocity with which the elevator ascends be u'

The height attained by the elevator at time, be h

Thus

    (1)_

Now, with the help of eqn (2) of motion, we can write:

Using eqn (1):

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.

overcharge is the right answer system