To solve this problem it is necessary to apply the concepts related to Dopler's Law. Dopler describes the change in frequency of a wave in relation to that of an observer who is in motion relative to the Source of the Wave.
It can be described as
c = Propagation speed of waves in the medium
= Speed of the receiver relative to the medium
= Speed of the source relative to the medium
Frequency emited by the source
The sign depends on whether the receiver or the source approach or move away from each other.
Our values are given by,
Velocity of car
velocity of motor
Velocity of sound
Frequency emited by the source
Replacing we have that
Therefore the frequency that hear the motorcyclist is 601.7Hz
The speed of an object in a set direction is its velocity.
a) 1.57 m/s
The sock spins once every 2.0 seconds, so its period is
T = 2.0 s
Therefore, the angular velocity of the sock is
The linear speed of the sock is given by
where
is the angular velocity
r = 0.50 m is the radius of the circular path of the sock
Substituting, we find:
B) Faster
In this case, the drum is twice as wide, so the new radius of the circular path of the sock is twice the previous one:
At the same time, the drum spins at the same frequency as before, therefore the angular frequency as not changed:
Therefore, the new linear speed would be:
And substituting,
So, we see that the linear speed has doubled.
Answer:
Option e) 320 s
Explanation:
Here, distance = 3.0 km = 3000 m
The velocity of boat when it is going upstream;
Upstream velocity = velocity of boat in still water - velocity of river flow
So, Upstream velocity
So,Time to go upstream
The velocity of boat when it is going downstream;
Downstream velocity = velocity of boat in still water + velocity of river flow
So, Downstream velocity
So,Time to go downstream
So, total time (t) =
Option E is the correct answer.
Answer:
Explanation:
5p - 14 = 8p + 4
5p = 8p + 18 <-- Moving constants to one side; add the same number of +14 to both sides.
-3p = 18. <-- The same thing with the variable itself.
p = -6 <-- Divide both sides by negative 3.