E-Pen InMotion E-Pen Manual de usuario descargar pdf (Pagina 5)

Frogs, Cannonballs, and Flying Fruit, Part 1

1. It’s time to start throwing things: frogs, cannonballs, flying fruit. The trajectory of flying objects is ruled by an equation called a

parabola. In its simplest form, a parabola looks like this:

y = ax

and has a shape like this:

a is a coefficient that tells you the shape of the parabola. If a is negative, the parabola will go up and then down (like the trajectory

of a rock you throw in the air). If a is positive, the parabola will go down and then up, like the shape of a chain hung between two

posts. If a has a small absolute value (is close to 0), the parabola will be flatter. If a has a large absolute value (is far from 0), the

parabola will be steeper.

2. Create a new project and name it “Frogs, Cannonballs, and Flying Fruit”.

3. Change the first costume of Sprite1 to something you want to fly through the air: a frog, a cannonball, a piece of fruit, etc. Change

the second costume to what that object looks like when it lands: a frog, an explosion, a piece of splattered fruit.

4. Drag a when green flag clicked block onto the scripts area, add clear and pen up blocks from Pen, and add a switch costume to

costume1 block from Looks.

5. Create two variables named x and y. Set x to -40 and y to -.05*x*x. Add a block to move to (x, y).

6. Add a pen down block from Pen.

7. Add a repeat 20 block. Inside it, add blocks to change x by 4, set y to -.05*x*x and move to (x, y).

8. After the repeat 20 block, add a switch costume to costume2 block.

9. Click the green flag. If you have ever played a video game in which characters jump or are shot through the air (think Angry

Birds), the motion should be familiar to you.

10. Save your project.

1 2 3 4 5 6 7 8 9 10 ... 14 15

Sin comentarios

E-Pen InMotion E-Pen Manual de usuario Pagina 5