Answer:
C. 590 mph

Explanation:
Given:
- velocity of jet,

- direction of velocity of jet, east relative to the ground
- velocity of Cessna,

- direction of velocity of Cessna, 60° north of west
Taking the x-axis alignment towards east and hence we have the velocity vector of the jet as reference.
Refer the attached schematic.
So,

&


Now the vector of relative velocity of Cessna with respect to jet:



Now the magnitude of this velocity:

is the relative velocity of Cessna with respect to the jet.
Answer:
4,524,660 N
Explanation:
Assuming the submarine's density is uniform, 1/9th of the submarine's mass is equal to the mass of the displaced water.
m/9 = (1026 kg/m³) (50 m³)
m = 461,700 kg
mg = 4,524,660 N
Answer:
The average speed for the entire run is 12 km/h.
Explanation:
The average speed is given by the following equation:

Where:
: is the total distance
: is the total time
If during the first hour, they ran a total of 13 kilometers and then, they ran 5.0 kilometers during the next half an hour we have:


Hence, the average speed is:

Therefore, the average speed for the entire run is 12 km/h.
I hope it helps you!