<span>It is not that jet engines perform better at higher altitude, but rather they are more fuel efficient. Performance is far greater at lower altitudes. Just think about when you are taking off and the airplane accelerates quickly and pitches way up. There's lots of extra thrust down low to allow that. The fuel/air ratio remains somewhat constant through the climb. As altitude increases, the air thin outs and therefore, so can the fuel flow. Airlines try for the most efficient routes and altitudes as possible to save money. They do however change altitudes in flight (higher or lower) when needed for weather and turbulence avoidance. --- And a note about the jet stream, it is relatively narrow and always curving, so the time an airliner would spend there is very short. And another thing, it flows mostly west to east isn't the U.S. so a westbound flight would be at a disadvantage. Airlines still fly high whether traveling East or West.</span>
The average speed of the motorist in the second half of the journey is determined as 7 km/h.
<h3>What is average speed?</h3>
The average speed of an object is the ratio of total distance to total time of motion.
- Let his average speed in the second half = x
21 = (35 + x) / 2
35 + x = 42
x = 42 - 35
x = 7 km/h
Thus, the average speed of the motorist in the second half of the journey is determined as 7 km/h.
Learn more about average speed here: brainly.com/question/6504879
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Displacement vectors of 6 km South 2 km North, 7 km South, and 5 km North combine to a total displacement of 6 km South.
Answer: Option A
<u>Explanation:</u>
The displacement vector represents the location change: the distance of separation from the start point to the end point is the displacement vector’ magnitude, and travelled direction denotes the displacement vector’ direction.
In figure, the illustration shows a new vector for the entire journey from beginning to end. In other words, C = A + B. The C vector is called the sum, or resultant vectors. When applying this concept to the given question, we can find the total displacement vector value. It is as follows:
Given:
6 km South 2 km North, 7 km South, and 5 km North
Total displacement, s = 6 km South - 2 km North + 7 km South - 5 km North
North and south lie in an opposite direction. Therefore, when combining all distances negative sign mentioned to denote the direction.
Total displacement, s = 13 km South - 7 km North
Total displacement, s = 6 km South
Newtons 3.law: Action = Reaction
If a body exerts a force on a rope of 400 N the rope exerts a force on the body of 400N also. So the tension in the rope is 400N. See pictures below.