Final answer:
The mechanical advantage of a lever is calculated using the formula MA = Length of Effort Arm / Length of Resistance Arm. It measures how many times a lever multiplies the effort force, where a longer effort arm means more force can be exerted for the same effort. The correct answer is option a and d.
Step-by-step explanation:
The formula for the mechanical advantage (MA) of a lever is MA = Length of Effort Arm (Le) / Length of Resistance Arm (Lr). In the context of a lever, mechanical advantage is a measure of the force amplification achieved by using the lever. It tells us how many times a lever multiplies the effort force. The longer the effort arm relative to the resistance arm, the more force the lever can exert with a given effort. The ideal mechanical advantage (IMA), which assumes no friction loss, is calculated by dividing the length of the effort arm by the length of the resistance arm. Therefore, the correct formula is option (a.) LEA/LRA = RF/EF, which can also be written as option (d.) MA = R/E = OF/IF, where 'R' stands for resistance force and 'E' for effort force.
For instance, if we consider a wheelbarrow, where the center of gravity of the wheelbarrow and its load has a perpendicular lever arm (Lr) of 5.50 cm and the hands have a perpendicular lever arm (Le) of 1.02 m, the mechanical advantage would be calculated as MA = Le / Lr. The efficiency of the lever comes into play when considering the actual work done, which takes into account the frictional losses and is calculated using the work input and output.