Final answer:
Mechanical devices like pulleys and lever systems are commonly used to lift loads to heights, such as a house's roof. Pulleys allow for a mechanical advantage, reducing the needed force by increasing the rope length pulled.
Step-by-step explanation:
To lift a load to the roof of a house, mechanical devices such as pulleys and lever systems can be used. The pulley system, often used in construction cranes, is one of the simple machines where mechanical advantage can be easily calculated. Counting the number of ropes supporting the load gives the ideal mechanical advantage (IMA). The higher the IMA, the less force needed, but one must pull more rope—specifically, N meters to lift the load by 1 meter. Another mechanical system is the lever, used in hydraulic and mechanical lever systems, like those seen in heavy machinery such as a backhoe.
A ladder can serve as a simple tool as well, but to calculate the forces on a ladder, such as the normal reaction and friction forces at its base when a person climbs it, one must consider the ladder's weight, the climber's weight, and distances from the ladder's points of support, aligning with the principles of statics in physics.