Question

До стіни сперта драбина масою 15 кг. Центр ваги драбини знаходиться на відстані 1/3 довжини від її верхнього кінця. Яку силу, спрямовану горизонтально, потрібно прикласти до середини драбини, щоб верхній її кінець не здійснював тиск на стіну? Кут між драбиною та стіною 45°

Answer 1

Объяснение:

F=200H

..............

Answer 2

To solve this problem, we can use the principle of moments. The moment of a force is the product of the force and the perpendicular distance from the point of rotation. In this case, the point of rotation is the center of gravity of the ladder.

Let's assume that the length of the ladder is L. According to the problem, the center of gravity of the ladder is located at a distance of 1/3L from its upper end. Therefore, the distance from the center of gravity to the upper end of the ladder is 2/3L.

To find the force required to prevent the upper end of the ladder from exerting pressure on the wall, we need to balance the moments about the center of gravity.

Step 1: Calculate the weight of the ladder

The weight of the ladder is given as 15 kg.

Step 2: Calculate the distance from the center of gravity to the point of rotation

The distance from the center of gravity to the upper end of the ladder is 2/3L.

Step 3: Calculate the force required

To balance the moments, the force required can be calculated using the formula:

Force x Distance from the center of gravity to the upper end of the ladder = Weight x Distance from the center of gravity to the point of rotation

Let's denote the force required as F.

F x (2/3L) = 15 kg x (1/3L)

Simplifying the equation:

F = (15 kg x (1/3L)) / (2/3L)

F = 15 kg / 2

F = 7.5 kg

Therefore, the force required to prevent the upper end of the ladder from exerting pressure on the wall is 7.5 kg.

Please note that the given problem does not specify the units for the force. Assuming the units are in kilograms (kg), the force required is 7.5 kg.