Answer:
1. telescope
2.

f- focal length
f- focal length r- the radius of curvature of the mirror

p-the distance of the object from the vertex of the mirror
l-the distance of the figure from the vertex of the mirror
The conservation of momentum states that the total momentum in a system is constant if there is no external force acting on the system. The total momentum in the gun bullet system is 0 so it must stay that way.
The momentum of the bullet is mv = 0.015*500=7.5
The momentum of the gun must be the same to keep the total momentum of the system equal to zero, so we know that p = 7.5 for the gun.
Substituting this in we get:
7.5=3.1x
x=7.5/3.1
x=2.42
So the speed of the gun is 2.4m/s.
C. have similar properties
(this is because they have the same number of electrons in the outer orbital)
Answer: The primacy effect occurs when you're more likely to remember words at the beginning of a list. A suggested reason for the primacy effect is that the initial items presented are most effectively stored in long-term memory because of the greater amount of processing devoted to them.
So B would be your answer
If only internal forces are doing work (no work done by external forces), then there is no change in the total amount of mechanical energy. The total mechanical energy is said to be conserved. ... In these situations, the sum of the kinetic and potential energy is everywhere the same.