Final answer:
It is false that high-voltage wires are wrapped in insulating material; they are not covered but held aloft by insulating connectors. It is true that non-essential personnel must not be under a slab being lifted for safety reasons.
Step-by-step explanation:
Understanding High-Voltage Wires and Jacking Operations
Regarding the question about high-voltage wires, it is false that these wires are wrapped in insulating material; instead, they are held aloft by insulating connectors but are not typically covered with an insulating layer because the air space around the wires serves as a sufficient insulator.
As for the statement about the employee during a jacking operation, it is true that no non-essential employee should be beneath a slab while it is being lifted for safety reasons.
In the case of the boy pushing a box up a ramp, the statement is false. While the ramp might be 1.0 m high and 3.0 m long, this does not directly indicate that the pushing force was exactly 100 N, because this does not account for additional factors such as friction and the angle of the ramp, which affect the actual force required.