Practise Edexcel A-Level Physics moment of a force through force times perpendicular distance, lever-arm geometry, pivot directions and angle changes.
The photograph shows a ladder that a person can use to climb into the roof space of a building.
Front view
Side view
When not in use, the ladder is stored in the roof space and the opening to the roof space is covered by a board. The board is hinged to the ceiling at one end.
The ladder is attached to the board by a rail, as shown below. A small block prevents the board from rotating into the roof space.
The weight of the board and rail is 50 N . The weight acts at a distance of 0.45 m from the hinge as shown.
The total length of the ladder is 2.70 m , with 0.85 m to the left of the hinge.
The weight of the ladder is 54 N . Assume the ladder is uniform.
A downward force is required to rotate the board away from the block. This force is applied 0.80 m from the hinge.
Determine the magnitude of this force.
Magnitude of force =