Here the problem is exposed. The behavior is not smooth, the object always has the same speed when it changes direction. If we want to reproduce the bucket’s nice movement in *peggle*, we need the **Sin **function.

The **Sin **function is one of the trigonometric functions that are used to **relate angles and lengths of right-angle triangles.** Only 3 of the trigonometric functions are wildly used in mathematics (**Sin**, Cos, Tan), and **Sin **is the most used in the mechanics of video games animations.

These functions simply return the **ratio **between **one side** of a right-angle triangle over **one other side**.

Here below is a **unit circle**, a circle with a radius of **one unit**, in which all the possibles shapes of a right-angle triangle can be drawn.