That statement is true
Retinal disparity : space between your eyes that allow binocular vision to create depth perception
Retinal Convergence : Space between your eyes that signal visual moves to the retina
They both will increases as an object get closer to the individual, allowing them acknowledge and observe the existence of the object
1 horsepower is equal to 746 W, so the power of the engine is

The power is also defined as the energy E per unit of time t:

Where the energy corresponds to the work done by the engine, which is

. Re-arranging the formula, we can calculate the time t needed to do this amount of work:
Distance = speed X time
In this example, the speed of the airplane = 840km. The time (that the question is asking)is how far can it travel in 1 hour.
So just plug in your numbers.
Distance = 840km X 1 hour = 840km/hour or 840km for short.
Personal space differs from culture to culture, though it is widely acknowledged that Europe and U.S have bigger personal space requirements that their counterparts in Asia.
Hakeem might not realize it but it’s commonly accepted for Americans to have a distance between four to twelve feet between one another in social settings, especially in professional ones. A distance of two feet is only acceptable if the individual is part of the person’s inner circle, such as friends and family.