Final answer:
To determine the position of the fulcrum in a Class I lever, you can use the principle of moments. For a 40kg load lifted by a 40N force, the fulcrum should be positioned 3.63m from the effort point or 0.37m from the load for equilibrium.
Step-by-step explanation:
To find the position of the fulcrum in a Class I lever lifting a load of 40kg with a force of 40N, we need to use the principle of moments. The principle of moments states that the sum of the moments about any point is equal to zero when the system is in equilibrium. A moment is the product of the force applied and the distance from the pivot point (fulcrum). For a Class I lever, the fulcrum is placed between the effort and the load. The condition for equilibrium is expressed as Effort × Effort Arm = Load × Load Arm.
Given that the total length of the lever is 4m, if we label the distance from the fulcrum to the point of applied effort as x, the distance from the fulcrum to the load will be (4m - x). The weight of the load in Newton is equivalent to 40kg × 9.8m/s² = 392N since weight is the product of mass and the acceleration due to gravity. With the force of 40N applied to the lever:
40N × x = 392N × (4m - x)
Solving for x, we get:
x = 392N × 4m / (392N + 40N)
x = 1568N·m / 432N
x = 3.63m (approximately)
Therefore, the fulcrum should be positioned approximately 3.63m from the point where the effort is applied, or 0.37m from the load to achieve equilibrium and lift the load with a force of 40N.