Selena's dog completed an obstacle course that was 452 meters long. There were four parts to the course, all equal length. How long was each part of the course?

113 meters long

Step-by-step explanation:

If each part is all equal in length, then each part is 1/4 the total length of the obstacle course. Therefore, each part of the course was 1/4(452)=113 meters long

reduce the friction between its moving parts

step-by-step explanation:

in fact, by reducing the friction between the moving parts of the machine, it is possible to reduce the energy wasted due to this friction; therefore, more input energy is converted into useful work, and this will improve the efficiency of the machine.

-2 is the right