Answer:

Explanation:
Here we can use energy conservation
As per energy conservation conditions we know that work done by external source is converted into kinetic energy of the disc
Now we have

now we know that work done is product of force and displacement
so here we have


now for moment of inertia of the disc we will have



now from above equation we will have


Answer:
Grow up man, this is completely based on your curriculum, we would need your book to answer, and this has to be done by you.
Work in general is given by W=F·d where F is the force vector and d is the displacement vector. The dot symbol is the dot product which is a measure of how parallel two vectors are. It can be replaced by the cosine of the angle between the two vectors and the vectors replaced by their magnitudes. If F and d are parallel then the angle is zero and the cosine is unity. So in this case work can be defined as the product of the magnitudes of the force and distance:
W=Fd
Water is a very unique substance because it can exist in all three phases of matter (solid, liquid, gas) within the normal temperature ranges found on Earth. When one observes the phase of matter of water, one observes a property of matter.