- Height (h) = 50 cm = 0.5 m

- Acceleration due to gravity (g) = 9.8 m/s²

To find:

- Speed (v) when the ball reaches the bottom of the plane.

Solution:

We can use the following equation to calculate the final speed of the ball:

```

v² = u² + 2gh

```

where:

- v is the final speed of the ball

- u is the initial speed of the ball (0 m/s, since the ball is at rest)

- g is the acceleration due to gravity

- h is the height from which the ball is dropped

Substituting the given values into the equation, we get:

```

v² = 0² + 2 * 9.8 m/s² * 0.5 m

v² = 9.8 m²/s²

v = √9.8 m²/s²

v = 3.13 m/s

```

Therefore, the speed of the ball when it reaches the bottom of the plane is 3.13 m/s.