Answer:
The value is 
Explanation:
From the question we are told that
The speed of the airplane from the north is 
The negative sign is because the direction is towards the south
The speed of the airplane from the east is 
The negative sign is because the direction is towards the west
The distance of the southbound plane from the airport is 
The distance of the westbound plane is 
Generally the distance between the plane is mathematically represented using Pythagoras theorem as

Next differentiate implicitly this equation to obtain the rate at which the distance between the planes changes
So

Here

=> 
=> 
=> 

=> 
=> 
Answer: F
Explanation: The boy is controlling the bowling ball therefore he can use greater force
To solve this exercise it is necessary to apply the concepts related to the Snells law.
The law defines that,

Incident index
Refracted index
= Incident angle
Refracted angle
Our values are given by


Refractory angle generated when light passes through the fiber.
Replacing we have,




Now for the calculation of the maximum angle we will subtract the minimum value previously found at the angle of 90 degrees which is the maximum. Then,

Therefore the critical angle for the light ray to remain insider the fiber is 28.6°
The mass of the water with the sugar dissolved in it is 55 grams. This is because when you add the weight of the water, and the sugar that you added, it is 55.
Answer:
D
Explanation:
When the sound is moving away from the stationary object the pitch decreases according to the Doppler Effect.