Answer:

Explanation:
= 14 km
= 49 km
Intensity of a wave is inversely proportional to distance

So,

The ratio of the intensities is 
Answer: Base units
The principal SI units that are used to derive all other SI units are called base units. The base units are the units of fundamental quantities e.g. M L T that is Mass, Length, and Time. All other physical quantities can be written in the fundamental dimension forms. The physical quantities are not measured directly but are build up from the building blocks that are the fundamental quantities which have base units.
Answer:
E) She can perform no measurement to determine this quantity.
Explanation:
A spacecraft is a machine used to fly in outer space.
According to Isaac Newton's third law of motion, every action produces an equal and opposite reaction. When fuel is shoot out of one end of the rocket, the rocket moves forward for which no air is required.
As Leah is moving in a spaceship at a constant velocity away from a group of stars, she cannot measure to determine this quantity.
Answer:
Wavelength λ = 7.31 × 10^-37 m
Explanation:
From De Broglie's equation;
λ = h/mv
Where;
λ = wavelength in meters
h = plank's constant = 6.626×10^-34 m^2 kg/s
m = mass in kg
v = velocity in m/s
Given;
v = 24 mi/h
Converting to m/s
v = 24mi/h × 0.447 m/s ×1/(mi/h)
v = 10.73m/s
m = 84.5kg
Substituting the values into the equation;
λ = (6.626×10^-34 m^2 kg/s)/(84.5kg × 10.73m/s)
λ = 7.31 × 10^-37 m
The sentences are invalid and unsound.
<h3><u>Explanation</u>:</h3>
The fire is defined as the vigorous oxidation of a substance. Now oxidation can occur in presence of any oxidising agent. Like magnesium in presence of nitrogen in high temperature with a dazzling brownish flame to produce magnesium nitride. So fire can be produced in absence of oxygen.
Oxygen is present everywhere in world. So production of a whole room without oxygen is very tough to produce and costly process. So its very unsound.