I. Work done by load is always less than the work done by effort. II. All machines are made of levers, pulleys, screws and gear wheels. III. A fishing rod i...

Answer Details

The question asks which statements about machines are true. Let's evaluate each statement: I. Work done by load is always less than the work done by effort. This statement is generally true for all machines because some of the work done by the effort is used to overcome friction and other resistive forces in the machine. Therefore, the statement is true. II. All machines are made of levers, pulleys, screws and gear wheels. This statement is not true as machines can be made of a variety of components including electronic parts, hydraulic systems, etc. Therefore, the statement is false. III. A fishing rod is a machine. This statement is true as a fishing rod is a simple machine that uses a lever to catch fish. Therefore, the statement is true. IV. Effort is always larger than load. This statement is not true because machines can be designed to have a load larger than the effort, such as in a hydraulic press. Therefore, the statement is false. From the above evaluations, we can see that the true statements about machines are I and III. Therefore, the correct answer is "I and III".