Key ideas1 of 3
Why the acceleration changes
A falling object has weight downwards and air resistance, or drag, upwards. In this example, weight stays at 10 N. In A, drag is 2 N, so the resultant force is 8 N downwards. As speed increases, drag increases. In B, drag is 6 N, giving a smaller resultant force of 4 N downwards. The object still speeds up, but its acceleration is smaller. The animation compares these stages of the same fall.
