Answer:
Only option A is correct
Explanation:
From the concept of Doppler effect, only speed matters. Thus, the faster a vehicle is moving, the closer together the sound waves get compressed and the higher the frequency. For example, for a very fast vehicle traveling at the speed of sound; the compressions are all right on top of each other. Thus, faster speed means closer compressions and higher frequencies. Hence, option only option A must be true because X is a higher frequency and so it must be going faster. The distance to the person will affect the volume but will not the pitch so Option B is not correct. Option C too is not correct because It doesn’t matter whether you are speeding up or slowing down, it only matters who is going faster. For example, from option c concept, if truck X was going 10 m/h and speeding up while truck Y was going 50 mph and slowing down, it would not meet the requirement that X has a higher frequency because only actual speed matters, not what is happening to that speed. Thus only option A is the correct answer
Answer:
Her speed at the bottom of the slope is 25.665 m/s
Explanation:
Here we have
Initial velocity, v₁= 15 m/s
Final velocity = v₂
The energy balance present in the system can be represented as
Where:
m = Mass of the cyclist = 70 kg
W = work done by the drag force = 
Where:
d = Distance traveled = 450 m
Therefore,
and
= 658.714 m²/s²
v₂ = 25.665 m/s
Her speed at the bottom of the slope = 25.665 m/s.
Answer is in the photo. I can only upload it to a file hosting service. link below!
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Matter: Toothpaste, Gasoline, Bacteria, Cell
Non-matter: Happiness, Sound.
<u>Explanation:
</u>
The substances which occupies mass or volume occupying space is known as matter. It comprises of those things that can be seen through the eyes and it may include things like water, plants, food, dresses, etc. It can be defined by color or hardness.
The substances that are made of energy without occupying space is known as non-matter substances. It can be classified as form of some energy. Some examples include light energy from torch, heat energy from fire and sound energy form whistle, etc.
The resultant of the two vectors is 141 km/h.
Explanation:
When two vectors are at right angles to each other, their resultant can be calculated by using the Pythagorean's theorem:
where
A is the magnitude of the first vector
B is the magnitude of the second vector
In this problem, we have two velocity vectors of magnitude
A = 100 km/h
B = 100 km/h
Substituting into the formula, we find their resultant:
Learn more about vector addition here:
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