Answer:
Explanation:
The strain is defined as the ratio of change of dimension of an object under a force:
where
is the change in length of the object
is the original length of the object
In this problem, we have and
, therefore the strain is
An example that illustrates the difference is the circular motion
Explanation:
Let's start by reminding the definition of the two quantities:
- Speed is a scalar quantity that tells "how fast" an object is moving, regardless of its direction of motion.
Speed can be calculate as:
where:
d is the distance travelled
t is the time taken
- Velocity is instead a vector quantity, given by:
where;
d is the displacement of the object (displacement is a a vector connecting the initial position to the final position of motion)
t is the time taken
Since it is a vector, velocity has both a magnitude and a direction, therefore it also takes into account the direction of motion of the object.
For an object in motion in a straight line, speed and velocity are the same. However, this is not always the case.
In fact, an example of motion in which the two quantities are different is the circular motion. Consider for example the object making one complete revolution along the circle. Therefore, its average speed is the ratio between the length of the perimeter (the distance) divided by the time taken:
where r is the radius of the circle.
However, the displacement of the object is zero (because the object returns to the starting point), and so the average velocity is also zero:
Learn more about speed and velocity:
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Answer:
The correct answer is option 'd': The frequency decreases and the intensity of the sound decreases.
Explanation:
1) <u>Effect on Frequency </u>
According to Doppler's effect of sound we have
for a source of sound moving away from the observer the relation between the observed and the original frequency is given by
where
c = speed of sound in air
is the velocity of observer of sound
is the velocity of source of sound
is the original frequency of sound
As we see the ratio is less than 1 thus the frequency of sound that the observer receives is less than that of source.
2) <u>Effect on Intensity:</u>
At a distance 'r' from source emitting a wave of Power 'P' is given by
As we see on increasing 'r' intensity of sound decreases.