Question

Which of the following statement is not true about machines?

Answer 1

The answer to this question is D or the last one 

Answer 2

The machine can affect the productivity in various ways.

The work done by a substance is is product of force and displacement.

Mathematically Work done W = FS   where F is the force and S is the distance travelled.

The most significantly machine changes the direction of force which is required to carry out the required work.By doing so, the machines can lessen or increase the force needed for the work.We may say that the machines change the size of the force.

A machine can affect the work done by changing the way in which the work is done.The vice versa is not true.The machine can not decrease the amount of work that is done

Hence the correct option will be the last one i.e machines decrease the amount of work that is done.