Monitoring systems may also use ____, which are devices that respond to a stimulus (such as heat, light, or pressure) and genera
1 answer:
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Given :
Thin hoop with a mass of 5.0 kg rotates about a perpendicular axis through its center.
A force F is exerted tangentially to the hoop. If the hoop’s radius is 2.0 m and it is rotating with an angular acceleration of 2.5 rad/s².
To Find :
The magnitude of F.
Solution :
Torque on hoop is given by :
( Moment of Inertia of hoop is MR² )
Putting value of M, R and α in above equation, we get :
Therefore, the magnitude of force F is 25 N.
Hence, this is the required solution.
Apparent frequency heard by the staff: 389 Hz
Explanation:
The phenomenon described in this situation is called Doppler effect.
Doppler effect occurs when there is a source emitting a wave in relative motion with respect an observer. In such situation, the frequency of the wave as perceived by the observer ("apparent frequency") is shifted from the real frequency of the sound ("proper frequency"). In particular:
- The observer perceives a higher frequency if the source is moving towards them
- The observer perceives a lower frequency if the source is moving away from them
The formula to calculate the apparent frequency in the Doppler effect is
where
f is the proper frequency
f' is the apparent frequency
v is the speed of the wave
is the velocity of the observer (positive if they are moving towards the source, negative if moving away)
is the velocity of the source (positive if it is moving away, negative if moving towards the observer)
First of all, in this problem we have to calculate the proper frequency of the sound wave emitted from the ambulance; we have:
v = 343 m/s (speed of sound wave)
(wavelength)
So the proper frequency is
Now we can calculate the apparent frequency heard by the staff at the hospital when the ambulance moves away; we have:
(velocity of the ambulance)
(velocity of the staff)
Substituting,
Learn more about frequency and wavelength:
#LearnwithBrainly
#1
so mass number = 238
mass number = protons + neutrons
given that
neutrons = 146
238 = protons + 146
protons = 92
#2
so mass number = 241
mass number = protons + neutrons
given that
Protons = 94
241 = 94 + neutrons
neutrons = 147
#3
A = mass number
Protons = 90
Neutrons = 137
A = protons + Neutrons
A = 90 + 137 = 227