I think your in the wrong section kid. This should be in Earth and Space Science.
A physical quantity is a property of a material or system that can be quantified by measurement. A physical quantity can be expressed as the combination of a numerical value and a unit. For example, the physical quantity mass can be quantified as n kg, where n is the numerical value and kg is the unit.
Answer:
two less protons and 4 less mass units
Explanation:
This is the answer.
Answer:
Part a)


Part b)


Explanation:
Initial speed of the flywheel is given as

initial angular speed is given as


Number of revolutions

angular displacement is given as


now we have



Part a)
final angular speed of the wheel is given as




Part b)
If the final angular speed becomes zero then time taken by the wheel is given as



Now total number of revolution that it makes is given as


