If the echo (the reflected sound) reaches your ear less than about
0.1 second after the original sound, your brain doesn't separate them,
and you're not aware of the echo even though it's there.
If the echo comes from, say, a wall, 0.1 second means you'd have to be
about 17 meters away from the wall. If you're closer than that, then the
echo reaches you in less than 0.1 second and you're not aware of it.
A. 30 meters . . .
No. You hear that echo easily
B. you're standing within range of both sounds . . .
No. You hear that echo easily, if you're at least 17 meters from the wall.
C. less than 0.1 second later . . .
That's it. The echo is there but your brain doesn't know it.
D. 21.5 meters
No. You hear that echo easily.
Answer:
NFC Near Field Communication
Explanation:
The Near Field Communication is a communication protocol, for extra short distance with a maximum of 10 centimeters, but usually used in 4 to 5 cm. Its intended to be used in contactless pay systems and in transportation card. Actually has been used to transfer multimedia from cell phones and other devices. The maximum data rate is around 424 kbit/s, with mean in 250 Kbp
Momentum = mass x velocity
m=7.3kg
v=20 m/s
momentum= 7.3(20) = 146 kg m/s
Answer:
98N and 147N
Explanation:
We have the following information:

We can find the static fricton force as follow,

Where N is the normal force (mg)

Static friction force at 147N is greater than the force applied hence body does not move.

They give off a particle to become stable.