Answer:
The answer is 0.8 m
Explanation:
According the attached diagram, if we take the momentum in the point 0:

Where
mD = mass of Diane = 64.2 kg
mJ = mass of Jack = 93.6 kg
Replacing:


Henry will lift 200 N load 20 m up a ladder in 40 s. While the Ricardo will take 400 N load in 80 seconds. So, For Henry to take 400 N load it will take him 80 seconds in two attempts. And,also, he will have to cover 40 m of distance.
Answer:
It is easier to scale the voltage of AC from high to low and low to high than with DC
Explanation:
typically power is used far away from the place where it's generated so to ensure that transmission losses( copper losses) are minimized voltage has to be stepped up during transmission..but due to the fact that most house hold equipment requires low voltage levels it has to be stepped down once it reaches a household/ domestic load...it's easier to do this for Ac than for DC.