<u><em>Answer</em></u>
A) 1,347.5 Joules
B) 22.49 m/s
<u><em>Explanation</em></u>
<u>Part A</u>
The work done by the gravity is known as potential energy.
It is given by;
P.E = mgh
Where m is mass, g is acceleration due to gravity and h is the vertical height.
P.E = 5.5 × 9.8 ×25
= 1,347.5 Joules.
<u>Part B</u>
Using the Newton's third Law of motion,
V² = U² +2as
Where v is final velocity, u is the initial velocity, and s is the displacement of the stone.
V² = 4² + (2×9.8×25)
= 16 + 490
= 506
V = √506
= 22.49 m/s
Answer: f = -12 cm
Explanation: <u>Combined</u> <u>lenses</u> is an array of simple lenses with a common axis. The combination is useful for correction of optical aberrations which cannot be corrected by simple lenses.
When two lenses are in contact and are thin, focal lengths are related as:
If there is a distance between the lenses, the focal length will be:
Since the lenses in the question above are thin and in contact, the focal length of one of them will be:
-12
The focal length of the other lens is -12 cm, with the negative sign meaning it's a converging lens.
On your list you can easily identify by knowing which is not a chemical change.
A physical change is a change not involving the material composition of the water. e.g. (melting, solidifying, evaporation). As long as the change does not change the molecular composition of the water which is H20 it is physical change.
<h2>Answer: remain stationary</h2>
Stationary waves (so called because they seem to be immobile) occur when two waves interfere with the <u>same frequency, amplitude but with different direction</u>, along a line with a phase difference of half wavelength.
In this kind of waves there are two types of points:
The nodes, which are points that remain motionless or stationary and do not vibrate. They are due to the destructive interference of both waves when they meet.
The antinodes, which are points that vibrate with a maximum vibration amplitude. They are due to the non-destructive interference of both waves.
According to this explanation and comparing it with the description, when this two waves pass through each other, the point P will become a node, hence<u> it will remain stationary</u>.
