# Physics (17/17)

# 1. start physics

• Make sure to activate the physics engine before using physics blocks. (Or no physics block is working!)

• Once the engine is enabled, the stage seems to have gravity as the sprite has gravity, mass, friction, ect.

• Application: this block can be used to create games like Super Mario Bros.

# 2. stop physics

• Once the physics engine is deactivated, all physics effects of the sprite will disappear.

# 3. [with] collision

• Set whether the sprite will collide with other sprites or not.

• If the sprite does not participate in a physical collision, other sprites will not have a physical collision effect when they encounter this sprite. Furthermore, Physics blocks would have no effect on this sprite, that is, no gravity, no mass, no rebound, and so on.

# 4. [enable] to fall

• Falling effect will appear if the sprite is enabled to fall when it is falling. Both the shape and the mass of sprite will affect the falling effect.

• Usually the larger the mass of the sprite, the more obvious the collision.

• Tip: with this block, you can create games like Angry Birds.

# 5. set gravitational acceleration to (10) at (-90) degrees

• Change the force degree and direction of the graviton acceleration.

  • Value range: -10000 to 10000

  • Force degree: the default value is 10. The greater the gravitational acceleration, the faster the velocity of the free-fall body.

  • Direction: the default direction is -90 degrees. When the derection is -90 degrees, the sprite falls directly down when start physics.

# 6. set gravitational acceleration to (10) with direction controlled by phone

• Set the gravitational accerlation, whose direction can be changed by tilting the phone.

  • Value range: -10000 to 10000

  • Force degree: the default value is 10. The greater the gravitational acceleration, the faster the velocity of the free-fall body.

  • When tilting a mobile phone, gravity is always consistent with the direction of real gravity, that is, vertical down.

# 7. set physical edge as [no edge]

• Set the physical edge of the stage when start physics. Collision can not happen beyond the edge.

  • The default style is [no edge].

  • 4 edges are available in drop-down list.

# 8. set mass to \10)

• The default mass of a sprite is related to its area. The larger the sprite, the greater the default mass.

• This block can set sprite's mass to input value.

  • Value range: 0~10000

# 9. set density to (1)

• Set the density of the sprite, which would affect sprite's mass.

  • Value range: 0 to 10000

  • In Kitten Editor, density = mass ÷ area

# 10. set friction coefficient to (0.5)

• The greater the friction coefficient, the greater the resistance of the sprite.

  • Value range: 0 to 1. Decimal value is available.

# 11. set restitution coefficient to (0.9)

• It is easy to achieve the rebound effect of elastic ball.

  • Value range: 0 to 1

# 12. set sprite material as [common]

• Set the sprite's material: mass, density, friction coefficient, and restitution coefficient.

  • 4 materials are available now: common, iron, wood and elastic.

# 13. [speed] of [itself]

• Get the sprite's physical properties like speed, mass, density, friction coefficient or restitution coefficient.

# 14. set speed to (5) at (0) degrees

• Set the instantaneous speed of a sprite at a certain time. The speed and direction can be changed.

• Tip:

  If you want the achieve jumping effect of a sprite, you can try these blocks.

  Set a proper speed, and direction from 45 degrees to 75 degrees is better~

  

# 15. set speed at X-axis to (5), Y-axis to (5)

• Input the speed at X-axis and Y-axis to set the instantaneous speed of a sprite at a certain time.

• It can determine the direction and speed of the sprite's movement.

# 16. set force to (5) at (0) degrees

• Set the force of a sprite at a certain time

# 17. set force at X-axis to (5), Y-axis to (5)

• Input the force at X-axis and Y-axis to set the sprite's state of stress at a certain time