Answer:
The pitch that he hears after the truck passes and is moving away is 819.6 Hz.
Explanation:
The pitch that he hears after the truck passes and is moving away can be calculated using the following equation:

Where:
: is the perceived frequency
: is the emitted frequency
: is the speed of sound = 340 m/s
: is the speed of the observer = 0 (he is not moving)
: is the speed of the fire truck
First, we need to find the speed of the fire truck. When it approaches the observer we have:




Hence, the speed of the fire truck is 25.05 m/s.
Now, we can calculate the pitch that the observer hears after the truck passes:



Therefore, the pitch that he hears after the truck passes and is moving away is 819.6 Hz.
I hope it helps you!
Answer:
1.86 × 10 ∧-3 V/m
≅ 1.9 × 10 ∧-3 V/m
Explanation:
Radius of long solenoid (R)= 3 cm
Turns per meter (n) = 2500
current flowing in coil (I) = 0.30 sin (200 t)
Time (t) = 2.5 ms
Distance at which electric field calculated (r) = 4 cm
The main solution is shown in the picture attached below.
Thank you and i hope it helps.
Answer: Heart can beat 140 times in = 2 minutes
Answer:
The weak nuclear force is one of the fundamental forces:
Is a force that is responsible of some radiative phenomenoms, like the beta decay.
The intensity is way smaller than the one of the strong interaction, but this is because it acts in a way smaller range. And this can produce atractive and repulsive interactions.
So options D and B can be discarded.
And this force can be repulsive or attractive depending on the phenomena, so the options that are wrong are A and B, because the interaction is both things, not only one.