Mark wanted to know how tall the tree in his front yard is. At the same time of day, he measured the length of his shadow and the length of the shadow cast by the tree. Mark, who is 5 feet tall, cast a shadow 10 feet long, and the tree's shadow was 140 feet long. How many feet tall is the tree?

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.