Oh no! I was distracted by that giant pencil hurling toward me so I tripped on this rock!
My Spidey-Sense is tingling!
The man was walking at a constant pace, then he was stopped to to the force of the rock. The pencil hurling toward him was accelerating at a constant rate, so it was an unbalanced force.
Just doin' my job.
Wow! You saved my life! Thank you!
The woman and the man are sitting down, and are still, they have balanced forces. Because the gravity pulling on them, is equivalent to the force of the chairs holding them up giving them a net force of 0N.
The superhero has a constant velocity until he is slowed down by slamming into the giant pencil, changing the pencils motion.
Wow, sure glad he saved me.
The two men's hands are coming at eachother with the same amount of force, creating a balanced force. When they collide they also create friction.
The superhero is accelerating as he flys away, making him an unbalanced force. While the other man is standing still, with the force of gravity being equal to the force of the ground supporting him, making him a balanced force
The superhero continues to accelerate after changing direction. While the man is now walking away, continually picking up speed as he goes. Making both of them unbalanced forces.