Question

Which of the following statements is incorrect?​
i) Friction acts on both liquids and gases.​
ii) Friction is only an evil. ​
iii) Fluid friction is least for streamlined objects.​

Answer 1

Let’s see all the statements one by one:
Friction acts on fluids. Hence statement (i) is correct
Though friction is evil as it damages various substances. But it is also necessary for us. We cannot move without friction, we cannot grip anything without friction, and many more things which are not possible without it.
So friction is not only evil. Hence statement (ii) is incorrect.
Fluid friction varies with the shape of the object. For the objects with streamlined shapes, it is the least. Hence, statement (iii) is also true.
So, only (ii) is incorrect.