Question

• (lever) a simple machine, consisting of a rigid beam and a fulcrum
• the fulcrum is the pivot point of the lever
• the input force (effort) is the force applied to the lever
• the output force (load) is the force that the lever exerts on another object
• in first - class levers, the fulcrum is located between the effort and the load
• in second - class levers, the load is located between the effort and the fulcrum

the student wants to contrast first - class levers and second - class levers. which choice most effectively uses relevant information from the notes to accomplish this goal?
a) in levers, the effort is the force applied to the lever; the load, in contrast, is the force that the lever exerts on another object.
b) in first - class and second - class levers, the fulcrum and the load are in different locations.
c) first - class levers are simple machines consisting of a rigid beam and a fulcrum, but then again the same is true of second - class levers.
d) in first - class levers, the fulcrum is located between the effort and the load, but in second - class levers, the load is located between the effort and the fulcrum

Explanation:

To contrast first - class and second - class levers, we need information that shows a difference between them.

• Option A: Describes effort and load in general for levers, not a contrast between the two types of levers.
• Option B: Is a very vague statement and does not clearly show the difference in the location of fulcrum and load between the two lever types.
• Option C: States that both first - class and second - class levers have a rigid beam and a fulcrum, which is a similarity, not a contrast.
• Option D: Clearly states the difference in the location of fulcrum (in first - class levers) and load (in second - class levers) between the two types of levers, which helps in contrasting them.

Answer:

D. In first - class levers, the fulcrum is located between the effort and the load, but in second - class levers, the load is located between the effort and the fulcrum.