Question 7
A wooden block is pulled with 20 N one way and 15 N the opposite way. What is the resultant force?
The right answer is the one marked above.
5 N, in the direction of the larger force. 20 N − 15 N = 5 N, acting the way the 20 N force acts, so the block moves that way.
Adding them to 35 N is wrong — forces are added only when they act in the same direction. Acting oppositely, they are subtracted.