57 335
Assignments Done
99%
Successfully Done
In February 2018
Your physics homework can be a real challenge, and the due date can be really close — feel free to use our assistance and get the desired result.
Be sure that math assignments completed by our experts will be error-free and done according to your instructions specified in the submitted order form.
Our experts will gladly share their knowledge and help you with programming homework. Keep up with the world’s newest programming trends.

Answer on Mechanics | Relativity Question for ABHYUDAY

Question #2719
TRAIN A IS MOVING WITH SPEED 1OOkm/hr & train b moving with speed 150 km/hr.train b whistles at 800Hz.In how much time a passenger sitting in train A will hear it?
Expert's answer
Train A is moving with speed 100 km/h and train B with speed 150 km/h. Train B whistles at 800 Hz. In how much time a passenger sitting in train A will hear it?
Let’s start. The general Formula is
ν= ν0 (s±V)/(s±v),
where: s - is the velocity of waves in the medium, V - is the velocity of the receiver (passenger in train A) relative to the medium; positive if the receiver is moving towards the source, v - is the velocity of the source (train B) relative to the medium; positive if the source is moving away from the receiver.
The initial frequency is 800 [Hz], so we get
ν= ν0 (s±V)/(s±v)= ν0 (s+V)/(s-v).
V=100 [km/h] = (100*1000[m])/(3600[sec])=27.7 [m/sec], v=150 [km/h] =41.6 [m/sec].
In dry air at 20 °C (68 °F), the speed of sound is 343.2 metres per second, so we get
ν= ν0 (s+V)/(s-v)= ν0 (s+V)/(s-v)=800[Hz] (343.2+27.7)/(343.2-41.6)=800[Hz]*370.9/301.6=800[Hz]*1.23=983.8[Hz].
If the trains are moving toward each other in other case
ν= ν0 (s+V)/(s+v)= ν0 (s+V)/(s+v)=800[Hz] (343.2+27.7)/(343.2+41.6)=800[Hz]*370.9/384.8=800[Hz]*0.96=773.1[Hz].

So the answer is ν=(983.8 Hz, 773.1Hz).

Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be first!

Leave a comment

Ask Your question