Answer:
The magnitude of the velocity of the aircraft P relative to aircraft Q is zero
Explanation:
The velocity of the two aircraft, P & Q, v = 300 m/s
The angle of the direction between them, Ф = 90°
The magnitude of the velocity of aircraft P relative to aircraft Q is given by the formula
<em> V = v cos Ф
</em>
Substituting the values in the above equation
v = 300 x cos 90°
= 300 x 0
= 0
Since the aircraft are at right angles, the velocity of one aircraft relative to the other is zero.
Answer: A) 
Explanation:
The equation for the moment of inertia 
of a sphere is:
(1)
Where:
is the moment of inertia of the planet (assumed with the shape of a sphere)
is the mass of the planet
is the radius of the planet
Isolating from (1):
(2)
Solving:
(3)
Finally:
Therefore, the correct option is A.
Answer:
d = 2021.6 km
Explanation:
We can solve this distance exercise with vectors, the easiest method s to find the components of the position of each plane and then use the Pythagorean theorem to find distance between them
Airplane 1
Height y₁ = 800m
Angle θ = 25°
cos 25 = x / r
sin 25 = z / r
x₁ = r cos 20
z₁ = r sin 25
x₁ = 18 103 cos 25 = 16,314 103 m
= 16314 m
z₁ = 18 103 sin 25 = 7,607 103 m= 7607 m
2 plane
Height y₂ = 1100 m
Angle θ = 20°
x₂ = 20 103 cos 25 = 18.126 103 m = 18126 m
z₂ = 20 103 without 25 = 8.452 103 m = 8452 m
The distance between the planes using the Pythagorean Theorem is
d² = (x₂-x₁)² + (y₂-y₁)² + (z₂-z₁)²2
Let's calculate
d² = (18126-16314)² + (1100-800)² + (8452-7607)²
d² = 3,283 106 +9 104 + 7,140 105
d² = (328.3 + 9 + 71.40) 10⁴
d = √(408.7 10⁴)
d = 20,216 10² m
d = 2021.6 km
Answer:
0.83 m or 5.57 m
Explanation:
Destructive interference will occur when the distances from the speakers differ by 1/2 wavelength.
The length of 1 cycle of 72.4 Hz is ...
λ = v/f = (343 m/s)/(72.4 Hz) ≈ 4.738 m
So, the distance of the listener from speaker B is ...
3.2 m ± (4.738 m)/2 = {0.83 m, 5.57 m} . . . either of these distances
_____
The location could be at additional multiples of 4.738 m, but we think not. The sound intensity drops off with the square of the distance from the speaker, so identical sound waves from the speakers will sound quite different at different distances from the speakers. For best interference, the distances need to be as close to the same as possible. That will be at 3.2 m and 5.57 m.
_____
<em>Comment on the speed of sound</em>
We don't know what speed you are to use for the speed of sound. We have used 343 m/s. Some sources use 340 m/s, which will give a result different by 2 or 3 cm.
I think that the girl has greater tangential acceleration because she is closer to the center and the acceleration is greater there.
