Opposing forces are at work all the time, even when you aren't moving! Physical processes -Force and motion - Action and reaction Learning Points When opposing forces are balanced, an object remains stationary. Unbalanced forces cause an object to change speed. Speed of movement changes with the balance of opposing forces. A Twig Curriculum Film. Delivering key learning points. Get straight to the facts in just three minutes – directly linked to core learning, Twig's curriculum films will fit neatly into your lesson plans.