Freefall Flashcards
Explanation
If the forces on an object are balanced, there is no resultant force. The object stays still, or carries on at a constant speed. If an object is standing still, then a force is needed to start it moving. If it is already moving, then a force is required to make it accelerate or decelerate. A force is also needed to make it change direction.
EG.
At start, a sky diver only has weight acting upon him, this unbalanced force makes him accelerate. As he travels faster, air resistance increases. When the two forces are equal, he travels at a constant speed (terminal velocity). When his parachute opens, air resistance increases which slows him down until the two forces are equal => forces are balanced so sum of forces is 0 => he travels at constant velocity.
