Answer:
108 km
Explanation:
The conversion factor between meters and feet is
1 m = 3.28 ft
So the second altitude, written in feet, can be rewritten in meters as

or in kilometers,

the first altitude in kilometers is

so the difference between the two altitudes is

Answer:
a) 1111.0 seconds
b) 833.3 s
c) Because of proportions
Explanation:
a) Total time of round trip is the sum of time upriver and time downriver

Time upriver is calculated with the net speed of student and 0.500 km:

(Becareful with units 0.5 km= 500m) Similarly of downriver:

So the sum is:

b) Still water does not affect student speed, so total time would be simply:

c) For the upriver trip, student moved half the distance in half speed of the calculation in b), so it kept the same ratio and therefore, same time. So the aditional time is actually the downriver.
Answer:
B. When the ball is released, the thrower's arm transfers its energy to the ball.