Question 6
Two forces act on an object and the resultant is zero. What does that mean?
The right answer is the one marked above.
Two equal forces act on the object in opposite directions. They cancel each other, but they are there.
A zero resultant is not the absence of force — in the third case of activity 2 both balances read 6 N and the trolley did not move. Mass has nothing to do with it.