Final answer:
To decrease the effort required to move a weight with a lever, one can increase the length of the effort arm, thereby increasing the mechanical advantage and reducing the effort force needed.
Step-by-step explanation:
The change that can be made to a lever to require less effort to move a weight is adjusting the length of the effort arm. By increasing the distance from the fulcrum to the point where the effort force is applied--essentially lengthening the effort arm--less force is required to lift or move a resistance or weight.
This is because the mechanical advantage (MA) increases with a longer effort arm. According to the principle of levers, work is the product of force and distance. When you apply a smaller effort over a longer distance on the effort arm, you can still lift heavy weights over a shorter distance at the resistance arm.
This incorporates the balancing of torques, where torque is the product of force and distance from the pivot. By configuring a lever to have a longer effort arm, you effectively diminish the effort needed to achieve the same amount of work.
A lever can be modified to require less effort or force to move a weight by making changes to the distance between the force (effort) and the fulcrum. The longer the distance between the force and the fulcrum, the less effort or force is required to move the weight. This can be achieved by moving the fulcrum closer to the weight or by extending the lever arm on the side of the force (effort).
For example, if you are using a pry bar to lift a heavy object, you can reduce the effort or force required by sliding the fulcrum closer to the object or by using a longer pry bar. This increases the lever arm on the side of the force, resulting in less effort or force needed to lift the object.