Given:
Horizontal distance between two boats = x = 14 m
One boat is at trough, the other is at crest.
As there is no crests between them meaning the boat are next to each other.
Wavelength is the distance between two consecutive crests/troughs = w
The distance between a crest and a trough next to it = w/2
Complete cycles = c = 5
Time taken for c cycles = t = 15 s
Vertical distance between two boats = y = 2.4 m
To find:
wavelength = w = 2x = 28 m
Amplitude = A = Displacement from mean to extreme position = y/2 = 1.2 m
Time period for one cycle = T = t/c = 15/5 = 3 s/cycle
frequency = 1/T = 1/3 = 0.33 hertz
speed = wavelength/Period = w/T = 28/3 = 9.33 m/s
Answer:
The number of free electrons per cubic meter is 
Explanation:
It is given that,
The number of free electrons per cubic meter is, 1.3
Electrical conductivity of metal, 
Density of metal, 
Atomic weight, A = 107.87 g/mol
Let n is the number of free electrons per cubic meter such that,


Where
is the density of silver atom
is the Avogadro number
A is the atomic weight of silver


or

Hence, this is the required solution.
Answer:
Energy can flow into and out of the system but matter cannot.
Explanation:
In a closed system, energy can flow in and out of the system but matter cannot.
- A closed system prevents double way flow of matter.
- A closed system conserves matter.
For an isolated system, energy and matter cannot flow out of the system.
For open systems, energy and matter can flow out of the system.
Such systems are used for certain thermodynamics experiment.
They’re right that is the answer