Answer: The focal length of the cornea-lens system in his eye must be LESS THAN the distance between the front and back of his eye.
Explanation:
The human eye the front part of the eye is the CORNEA. This is the tough white transparent part of the eye that helps in the refraction of light rays. While the backside of the eye is the RETINA. This is the part of the eye when images are focused.
When a normal eye is at rest, parallel rays from a distant object are focused on the retina. The ability of the eye - lens to focus points at different distances on the retina is known as accomodation. The adjustment of the eye lens to focus objects of varying distances is brought about by the ciliary muscles. The have the ability to change the shape of the eye which leads to change in focal length.
When a person with normal vision looks at a distant object at infinity, the lens brings parallel rays to focus on the retina. Thus, the furthest point which the eye can see distinctly is called the far point of the eye and it's infinity for a normal eye. But Joe was able to focus his eye on the tree, meaning that the tree was within his near point. This is the nearest point at which an object is clearly seen. Therefore, when the effective focal length of the cornea-lens system changes, it changes the location of the image of any object in one's field of view.
Answer:
Explanation:
1- Density increase as the temperature decreases. This is the reason why liquid water is more dense than solid water.
2- The only things that affect the period of a simple pendulum are its length and the acceleration due to gravity.
3- not really sure for that one...I will think about that.
4- same reason for number 3
Answer:
mass and volume
Explanation:
matter is anything that has mass and occupies space(volume)
Answer:
A) 1000 joules
Explanation:
In general work is given by the equation:
(1)
A) With 
the displacement and 
the force applied, because the force and the displacement are parallel (the crate is pushed horizontally) 
is simply 
, and because the path is a straight line and the force is constant work is:
(2),
B) The work-energy theorem says that the total work on a body is equal to the change on kinetic energy:
(3)
The total work on the crate is the work done by the push and plus the work of the friction 
(4) , as (A) because forces are parallel to the displacement 
(5) and 
(6), the due friction always has negative sign because is opposite to the displacement, using (6), (5) and (4) on (3):
(3)
C) The energy is lost by friction, so the amount of energy turned into heat is the work the friction does:
(3)
