Because the eyepiece lens just needs to refract off of the objective lens and so the objective lens needs to be bigger so you can see something from a distance I hope this helps
Answer:
a)
, b)
, c) 
Explanation:
a) The speed of the ball is determined by applying the Principle of Energy Conservation:

The speed of the ball when the string makes an angle of 12° with the vertical is:

![\frac{1}{2}\cdot m \cdot v^{2} = m\cdot g \cdot L \cdot [(1-\cos \theta_{1})-(1 -\cos \theta_{2})]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%5Ccdot%20m%20%5Ccdot%20v%5E%7B2%7D%20%3D%20m%5Ccdot%20g%20%5Ccdot%20L%20%5Ccdot%20%5B%281-%5Ccos%20%5Ctheta_%7B1%7D%29-%281%20-%5Ccos%20%5Ctheta_%7B2%7D%29%5D)



b) The maximum speed of the ball is:



c) The angle between the string and the vertical when the speed of the ball is one-third its maximum value is obtained by proving different values of
. The solution is approximately:

The wave diagramed in blue.
Explanation:
c) is equal to the momentum of the fired bullet
Electrons couldn't orbit the nucleus like miniature planets~!