Final answer:
To maintain safety, always maintain three points of contact on a scaffold ladder. The forces at the base and top of the ladder, when a person is climbing, can be calculated using static equilibrium, considering the pivot at the base of the ladder and the forces acting on it.
Step-by-step explanation:
When climbing up or down on a scaffold ladder, it is essential to maintain three points of contact to ensure safety. This means two hands and one foot or two feet and one hand should be in contact with the ladder at all times. Regarding the forces on a ladder against a wall as described in the scenarios, we can apply the principles of statics to determine the forces at play.
The normal reaction and the static friction at the base of the ladder, and the magnitudes of the forces on the ladder at the top and bottom, can be found by setting up equations for the sum of the torques and the sum of the forces in both the horizontal and vertical directions.
For example, if we consider a person of mass 70.0 kg standing 3 m from the bottom on a 6 m ladder of mass 10.0 kg, with the base of the ladder 2 m from the house, we can calculate the forces at the base by considering the pivot at the base of the ladder. The weight of the person and the ladder act downwards, while the normal force acts upwards and the friction force acts horizontally.
Since the wall is assumed frictionless, the ladder only experiences a normal force at the top. By applying the conditions for static equilibrium, where the sum of horizontal forces, the sum of vertical forces, and the sum of torques are zero, the values of these forces can be computed precisely.