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The Cartesian coordinate system The position of sprites on the Stage in the Scratch programming interface is based on a two-dimensional Cartesian coordinate system with the origin at the center of the Stage. The x coordinates range from-240 at the left to +240 at the right. The y coordinates range from +180 at the top to -180 at the bottom.

Three sprites

The area below the stage in Image 4 shows that this program contains two beachballs and one basketball in addition to the Stage. (The beachballs and the basketball are sprites.)

You add a sprite to your program by clicking one of the four buttons immediately below the stage.If you hover your mouse over those buttons going from left to right, the following tooltips appear:

  1. Choose a sprite from library
  2. Paint new sprite
  3. Upload sprite from file
  4. New sprite from camera

In this program, the beachballs and the basketball were added by selecting the first or leftmost button in the row of four buttons and then selecting theappropriate sprite from the library.

Although not visible in the cropped version of the programming interface in Image 4 , when you click on one of the sprites that you have added to the program, thatsprite appears at the top of the rightmost pane. (See Image 6 for example.) Having done that, you can then drag programming blocks into the rightmost pane that define the behavior of thatsprite.

Program code for the LeftBeachball

The code that I wrote (by dragging blocks into the rightmost pane in the programming interface) for the sprite named LeftBeachball is shown in Image 6 . (Note the image of the beachball in the upper right corner. When this is an image of a beachball, all of the scripts in the rightmost panel apply tothat particular beachball sprite.)

Image 6. program code for the left beachball.

Missing image.
Image 6. Program code for the left beachball.

You are already familiar with the tan block with the green flag shown in Image 6 because you learned about it in a previous module. However, theblue block in Image 6 has not been used prior to this module.

Adding the blue go to block to the program

The blue block shown in Image 6 was added to the program module by:

  • Clicking the dark blue button labeled Motion in the upper center of Image 4 .
  • Dragging the blue block shown in Image 6 from the toolbox to therightmost panel and clicking it into place under the tan block.
  • Typing the literal values -200 and 0 into the two white boxes on the blue block.

Coordinate values

If you move the mouse pointer around the stage in the programming interface, the coordinates of the mouse pointer are displayed immediately below the stage as shown in Image 4 . As mentioned earlier, the xcoordinates range from -240 at the left to +240 at the right. The y coordinates range from +180 at the top to -180 at the bottom.

Behavior of the LeftBeachball

The behavior of the script shown in Image 6 can be interpreted as follows: When the user clicks the green flag, cause the sprite named LeftBeachball to move to a location with an x (horizontal) coordinate value of -200 and a y (vertical) coordinate value of 0. Since the origin is at the center of the Stage, this causes the beachball to move to theleft of the origin on the horizontal axis.

Questions & Answers

A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
Aislinn Reply
cm
tijani
what is titration
John Reply
what is physics
Siyaka Reply
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Jude Reply
Can you compute that for me. Ty
Jude
what is the dimension formula of energy?
David Reply
what is viscosity?
David
what is inorganic
emma Reply
what is chemistry
Youesf Reply
what is inorganic
emma
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
Krampah Reply
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
Sahid Reply
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
Samuel Reply
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Joseph Reply
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
Ryan
what's motion
Maurice Reply
what are the types of wave
Maurice
answer
Magreth
progressive wave
Magreth
hello friend how are you
Muhammad Reply
fine, how about you?
Mohammed
hi
Mujahid
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?
yasuo Reply
Who can show me the full solution in this problem?
Reofrir Reply
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Source:  OpenStax, Teaching beginners to code. OpenStax CNX. May 27, 2013 Download for free at http://cnx.org/content/col11498/1.20
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