Question 8
In activity 2, a force of 4 N is applied to spring balance A and 6 N to spring balance B on the opposite side. What happens?
The right answer is the one marked above.
The trolley moves towards B with a resultant of 2 N. The extra force applied in the B direction over the A direction is 6 N − 4 N = 2 N.
10 N is the two forces added, which is wrong because they act in opposite directions. The trolley stays still only when the forces are equal; here they are not.