Janice is given a mixture of alcohol and water the teacher tells her that she can use temperature to separate these compounds wh
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Answer:
Here the source is moving away from the observer so frequency will be smaller than the actual frequency and since the speed is increasing so the frequency is decreasing with time so correct answer is
D) lower than the original pitch and decreasing as he falls.
Explanation:
As we know by the Doppler's effect of sound we have
so we will have
so here when source moves away from the observer with a some speed then the frequency of the sound observed by the observer is smaller than the actual frequency
Here we know that the speed of the source is increasing with time as the source is falling under gravity
So we can say that the pitch of the sound will decrease with time
As per the question the mass of two falling sky drivers is 132 kg.
First we have to calculate their acceleration.
Whenever a body falls freely under gravity,its acceleration is acceleration due to gravity i.e g whose value is 9.8 m/s^2.
The earth pulls the object with a force equal to the weight of the body.
Hence the force gravity F=W= mg [ here m is mass of the body]
Here m =132 kg.
Hence force of gravity F= mg
=132 kg ×9.8 m/s^2
=1293.6 kg m/s^2
=1293.6 N [ here N[newton] is the unit of force.]
As per the question the air resistance is one fourth of weight of the bodies.
Hence air resistance F' =1/4 mg
Here F acts in vertically downward direction while F' acts in vertically upward direction.
Hence the net force acting on the particle is F-F'.
From Newton's second law of motion we know that net force is the product of mass and acceleration i.e
[Here a is the acceleration]
In the second question it has been told that they descend with uniform speed.hence acceleration of the two bodies will be zero.
we know that F= ma
=m×0
=0 N
Hence they will not get any force when they will descend with a uniform speed.