Question

Assertion (A): In a practical simple machine work done by the effort is always equal to the work done on the load.

Reason (R): No energy is lost in a simple machine.

• A. A and R are true and R is the correct explanation of A.
• B. A and R are true, but R is not the correct explanation of A.
• C. A is true but R is false.
• D. Both A and R are false.

Answer 1

The correct option is D

Both A and R are false.

The explanation for the assertion

1. In any practical machine work done by the machine is always less than the work done on the machine. In other words, we can say that the work done on the load is always less than the work done by the effort.
2. This happens because energy loss takes place in many ways in a practical simple machine for example some energy is lost in the form of heat.

The explanation for the reason statement

1. In any practical simple machine loss of energy takes place in many ways some energy is lost in overcoming the force of friction some energy is lost in the form of heat.
2. If no energy loss takes place then it is called an ideal machine and practically it is not possible.

Hence the correct option is (D) Both A and R are false.