Object 1 is moving because the unbalanced force acting on the skateboard is causing it to <em>either move slower or move faster.</em> An example of this is when the skateboard is going down the hill. The unbalanced force is caused by the gravity which speeds up the skateboard.
Object 2 is also moving although it has a balance force; however, it is moving at a<em> "constant speed."</em> This is because the force of thrusting forward is being counteracted by a friction force of the <u>same magnitude.</u> Forces that are equal in magnitude and of opposing directions causing the speed to be constant. So, the bicycle is still moving.
