Alarge wooden turntable in the shape of a flat uniform disk has a radius of 2.00 m and a total mass of 100 kg . the turntable is initially rotating at 4.00 rad/s about a vertical axis through its center. suddenly, a 65.0-kg parachutist makes a soft landing on the turntable at a point near the outer edge.
1. find the angular speed of the turntable after the parachutist lands. (assume that you can treat the parachutist as a particle.)2. compute the kinetic energy of the system before and after the parachutist lands. why are these kinetic energies not equal?

Part 1)

Part 2)

initial kinetic energy of the system

Final kinetic energy is given as

Energy is decreased due to friction between parachutist and the disc

Explanation:

Part a)

As we know that the system of turn table and parachutist is isolated and there is no external force on this system

So here we can use angular momentum conservation for this

Part 2)

initial kinetic energy of the system

Final kinetic energy is given as

Energy is decreased due to friction between parachutist and the disc

answer; /// the above statement is (true);

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.