I think it is D because gas particles move the fastest but if not then it is A
A radar receiver indicates that a pulse return as an echo in 20 μs after it was sent. The reflecting object would be 3000 m away .
Phenomenon of hearing back our own sound is called an echo. It is due to successive reflection of sound waves from the surfaces or obstacles of large size. To hear an echo, there must be a time gap of 0.1 second in original sound and the reflected sound.
Given
time = 20 μs = 20 *
s
let distance to the reflecting surface be = x
total distance travelled by pulse will be = 2x
speed = 3.0 ×
m/s
distance = speed * time
2x = 3.0 ×
* 20 *
x = 3000 m
The reflecting object would be 3000 m away
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High task repitition, forceful exertions, repetitive or sustained awkward posture
<span>2 characteristics of stars are shown in an H-R diagram is S</span>ize and Color.
Answer:
The International Space Station move at 7.22 km/s.
Explanation:
Orbital speed of satellite is given by
, where G is gravitational constant, M is mass of Earth and r is the distance to satellite from centre of Earth.
r = R + h = 6350 + 1400 = 7750 km = 7.75 x 10⁶ m
G = 6.673 x 10⁻¹¹ Nm²/kg²
M = 5.98 x 10²⁴ kg
Substituting

The International Space Station move at 7.22 km/s.