Final answer:
The force applied to lift a crate using a lever can be calculated using the principle of moments. A force of 100 N applied to a lever arm of 0.21 m can be used to find the output force on a resistance arm of 0.28 m. C. 100 N is correct answer.
Step-by-step explanation:
The question involves calculating the force applied to lift a crate using a lever. This type of problem is commonly addressed in physics, where concepts of mechanical advantage and levers are discussed. Here, the lever's efficiency and the principle of moments (or torques) are key to solving the problem.
As per the principle of moments, the force times the distance (moment) on one side of the lever must equal the force times the distance on the other side, assuming the lever is in equilibrium.
To find the force with which the crate is lifted, we can set up the equation based on the principle of moments: Input Force × Effort Arm Length = Output Force × Resistance Arm Length.
Therefore, using the given values, we have 100 N × 0.21 m = Output Force × 0.28 m. Solving this equation for the Output Force gives us Output Force = (100 N × 0.21 m) / 0.28 m, which equals 75 N. However, since this value is not listed in the answer options, we might need to check our calculations or assumptions.