10th Class Karachi Board Exams Quizzes MCQs Quizzes Karachi Board 10th Class Physics Online Test 12

Question:
A screw jack always has an efficiency less than 100%

Option A):
There is always a frictional force between its parts
Option B):
A screw is really an inclined plane
Option C):
This must be so because of the definition of screw jack. Itch

Correct Answer is Option A):
There is always a frictional force between its parts