Question

1. На рычаг, плечи которого равны 10 см и 30 см, действуют две силы, перпендикулярные рычагу. Сила, действующая на короткое плечо, равна 3 Н. Чему должна быть равна сила, действующая на длинное плечо, чтобы рычаг оставался в равновесии?

Answer 1

1 Н, по правилу равновесия рычага

Answer 2

Calculation of Forces on a Lever

To determine the force required to keep the lever in equilibrium, we can use the principle of moments. The principle of moments states that for an object to be in equilibrium, the sum of the clockwise moments must be equal to the sum of the counterclockwise moments.

In this case, we have a lever with two perpendicular forces acting on it. The lever has two arms, one with a length of 10 cm and the other with a length of 30 cm. The force acting on the short arm is 3 N.

Let's denote the force acting on the short arm as F1 and the force acting on the long arm as F2.

According to the principle of moments, the clockwise moment (M1) created by the force F1 is equal to the counterclockwise moment (M2) created by the force F2.

The formula for calculating the moment of a force is:

M = F × l

Where M is the moment, F is the force, and l is the length of the lever arm.

Using this formula, we can calculate the moments created by the forces:

M1 = F1 × l1 = 3 N × 10 cm = 30 N·cm M2 = F2 × l2

Since the lever is in equilibrium, M1 must be equal to M2:

M1 = M2

Substituting the values:

30 N·cm = F2 × 30 cm

Simplifying the equation:

F2 = 30 N·cm / 30 cm

F2 = 1 N

Therefore, the force acting on the long arm of the lever must be 1 N in order to keep the lever in equilibrium.