Question

Кабина лифта,на которую действует сила тяжести 2.5 кH,поднимается из шахты на тросе.При этом в начале подъёма сила натяжения троса была равна 3 кH.Вычеслите равнодействующую силу в начале движения;в середине;и изобразите графически.

Answer 1

На кабину лифта действуют две силы - натяжения троса Т направленная вверх и  сила тяжести Р. Графически - квадратик с двумя стрелками вверх и вниз, Т и Р  Равнодействующая сила  равна Т-Р (раз лифт идет вверх),
она равна 3 кН-2,5 кН=0,5 кН
Видим, что лифт движется с ускорением, поскольку равнодействующая не равна 0 и это ускорение направлено вверх. Поскольку между этажами лифт идет без ускорения и Р=Т в задаче и говорится о начале движения (с ускорением)

Answer 2

Calculation of Resultant Force in the Elevator Cabin

To calculate the resultant force in the elevator cabin at different points during the ascent, we need to consider the forces acting on the cabin. The forces involved are the force of gravity and the tension force in the rope.

Given information: - Force of gravity (weight of the cabin): 2.5 kH - Initial tension force in the rope: 3 kH

Resultant Force at the Beginning of the Motion

At the beginning of the motion, when the elevator cabin starts to ascend, the resultant force can be calculated by subtracting the force of gravity from the initial tension force in the rope.

Resultant force at the beginning of the motion = Initial tension force - Force of gravity

Substituting the given values: Resultant force at the beginning of the motion = 3 kH - 2.5 kH = 0.5 kH

Therefore, the resultant force at the beginning of the motion is 0.5 kH.

Resultant Force in the Middle of the Motion

To calculate the resultant force in the middle of the motion, we need to consider the change in the tension force in the rope as the elevator cabin ascends.

As the elevator cabin moves upward, the tension force in the rope decreases due to the reduction in the force of gravity acting on the cabin. This is because the weight of the cabin is partially balanced by the upward force exerted by the tension in the rope.

To calculate the resultant force in the middle of the motion, we need more information about the specific position or distance traveled by the elevator cabin. Without this information, it is not possible to determine the exact resultant force in the middle of the motion.

Graphical Representation

To graphically represent the forces acting on the elevator cabin during the ascent, we can use