1. Change in Speed: When unbalanced forces act on an object, they can cause it to speed up or slow down.
* Example: A car accelerating from a stoplight has unbalanced forces (engine pushing forward, friction resisting). The car speeds up. A car braking to a stop also has unbalanced forces (brakes pushing backward, friction still resisting). The car slows down.
2. Change in Direction: Even if an object maintains a constant speed, unbalanced forces can cause it to change direction.
* Example: A ball thrown horizontally will travel in a curved path due to the constant downward force of gravity. The ball's speed might remain relatively constant, but its direction is continuously changing.
3. Change in Both Speed and Direction: The most common scenario is when unbalanced forces cause a change in both speed and direction.
* Example: A rocket launching into space. The rocket engine provides a large, unbalanced force, causing the rocket to both speed up and change direction as it leaves Earth's atmosphere.
Key Point: Unbalanced forces always lead to a change in velocity. The change in velocity is directly proportional to the net force (the sum of all forces acting on the object) and inversely proportional to the object's mass. This is described by Newton's Second Law of Motion: Force = Mass x Acceleration.
