Question

An oar is used to row a boat. The distance between the oar lock (fulcrum) and the rower’s hand is $104\,cm$. This distance is considered
A. the effort distance
B. the resistance distance
C. the mechanical advantage of the oar
D. the effort force

Answer 1

Hint-
We know that in a class 1 lever the load will be at one end. Force or effort will be applied at the other end and the fulcrum or the point of pivot of the liver will be in between. The distance from the point of pivot to the point of application of effort is known as the effort distance or the effort arm. And the distance from the point of pivot to the Load which is also called the resistance is the resistance distance.

Step by step solution:
When an ore is used to row the boat, the force which is also known as the effort is applied at one end of the ore with the help of our hand. At the other end the load which is the water is pushed back. As a result of which the boat moves forward.
It is given that oarlock is the fulcrum. This is an example of a class 1 lever. In a class 1 lever the load will be at one end. Force or effort will be applied a t the other end and the fulcrum or the point of pivot of the liver will be in between.

The distance from the point of pivot to the point of application of effort is known as the effort distance or the effort arm. And the distance from the point of pivot to the Load which is also called the resistance is the resistance distance.
Here the distance between oar Lock and rower’s hand is given as $104\,cm$. This distance is clearly the distance between the applied force and the fulcrum. So this distance will be the effort distance.

Note:
The oar is also considered as a second class lever with the perspective that the water forms the fulcrum oarlock is the load and force given by the hand is the effort. A second class lever is a liver in which the load is between the effort and the fulcrum. In this question it is specified that oarlock is taken as the fulcrum hence we can say it is a first class lever.