Exercise 5 under Activities asks you to

• set the ball's initial position to _i = (20,-10) m,
• drag the ball in a straight line to (20,-20) m,
• drag it in a straight line to (-15,-20) m,
• and drag it in a straight line to the final position _f = (-15,15) m.

The following diagram illustrates the situation. The path traveled by the ball is shown in blue, the displacement vector in green.

What is the ball's overall displacement = D, expressed in x and y components?

= D = _f - _i

= (-15, 15) - (20, -10) = (-15-20, 15-(-10)) = (-35, 25) m.