I think the correct answer is C
Answer:
Explanation:
distance of fan A = 18.3 m
distance of fan B = 127 m
speed of sound (s) = 343 m/s
What is the time difference between hearing the sound at the two locations?
time (T) = distance / speed
- time for sound to reach fan A = 18.3 / 343 = 0.053 s
- time it takes for sound to reach fan B = 127 / 343 = 0.370 s
- time difference = 0.370 - 0.053 = 0.317 s
The message is the information being communicated from one place to another.
It used to be called the "intelligence". But as time went on, it became
harder to ignore the obvious fact that that was going too far, and the
label was changed to the more IQ-neutral "message".
Answer:
gexp = 3.65 m/s²
Explanation:
The value of acceleration due to gravity changes with the altitude. The following formula gives the value of acceleration due to gravity at some altitude from the sea level:
gexp = g(1 - 2h/Re)
where,
gexp = expected value of g at altitude = ?
g = acceleration due to gravity at sea level = 9.8 m/s²
h = altitude = 2000 km = 2 x 10⁶ m
Re = Radius of Earth = 6.37 x 10⁶ m
Therefore,
gexp = (9.8 m/s²)(1 - 2*2 x 10⁶ m/6.37 x 10⁶ m)
<u>gexp = 3.65 m/s²</u>
As we know that reaction time will be
![t = 0.50 s](https://tex.z-dn.net/?f=t%20%3D%200.50%20s)
so the distance moved by car in reaction time
![d = vt](https://tex.z-dn.net/?f=d%20%3D%20vt)
![d = 20 \times 0.50](https://tex.z-dn.net/?f=d%20%3D%2020%20%5Ctimes%200.50)
![d = 10 m](https://tex.z-dn.net/?f=d%20%3D%2010%20m)
now the distance remain after that from intersection point is given by
![d = 110 - 10 = 100 m](https://tex.z-dn.net/?f=d%20%3D%20110%20-%2010%20%3D%20100%20m)
So our distance from the intersection will be 100 m when we apply brakes
now this distance should be covered till the car will stop
so here we will have
![v_f = 0](https://tex.z-dn.net/?f=v_f%20%3D%200)
![v_i = 20 m/s](https://tex.z-dn.net/?f=v_i%20%3D%2020%20m%2Fs)
now from kinematics equation we will have
![v_f^2 - v_i^2 = 2 a d](https://tex.z-dn.net/?f=v_f%5E2%20-%20v_i%5E2%20%3D%202%20a%20d)
![0 - 20^2 = 2(a)100](https://tex.z-dn.net/?f=0%20-%2020%5E2%20%3D%202%28a%29100)
![a = \frac{-400}{200} = -2 m/s^2](https://tex.z-dn.net/?f=a%20%3D%20%5Cfrac%7B-400%7D%7B200%7D%20%3D%20-2%20m%2Fs%5E2)
so the acceleration required by brakes is -2 m/s/s
Now total time taken to stop the car after applying brakes will be given as
![v_f - v_i = at](https://tex.z-dn.net/?f=v_f%20-%20v_i%20%3D%20at)
![0 - 20 = -2 (t)](https://tex.z-dn.net/?f=0%20-%2020%20%3D%20-2%20%28t%29)
![t = 10 s](https://tex.z-dn.net/?f=t%20%3D%2010%20s)
total time to stop the car is given as
![T = 10 s + 0.5 s = 10.5 s](https://tex.z-dn.net/?f=T%20%3D%2010%20s%20%2B%200.5%20s%20%3D%2010.5%20s)