Friday, November 1, 2013

Day 2 Rocket Model building

Day 2 Rocket Model building https://sites.google.com/a/moe.edu.sg/rocketbuilding/homework/lesson2
https://sites.google.com/a/moe.edu.sg/rocketbuilding/ thanks to @engrg1
http://tinyurl.com/hgssrocket

some activities for model building



Task 1: the real rocket should stop when it hits the ground. make simulation pause
                                                                                         if ( y<0 font="">    _pause();}

Task 2: make rocket rotate at the top of the motion
                                        if (vy>0){  rotate = 0;  }  else if (vy<0 font="">    rotate = pi;    }
hint: you need to declare the variable rotate in the Variables page.


Task 3: add the Mass of fuel mFuel as a slider
goto View and add a slider called mFuel and has the values as shown in the picture



Task 4a: add the Mass of rocket as a slider
goto View and add a slider called m and has the values as shown in the picture

Task 4b: add the Mass of rocket as a input field
goto View and add a field called m and has the values as shown in the picture

Task 5: is gravity constant as the rocket moves up to outer-space?
here, physics is important to implement the appropriate solution to work out the gravity at height y, based on the knowledge that gravity on Earth's surface is about 9.81 m/s^2  
// because g = G Mearth /r^2
//therefore the ratio
// g/gs = 1/( y+Rearth)^2 / 1/Rearth^2

g = gs*Rearth*Rearth/( (y+Rearth)*(y+Rearth) );
goto fixed relationship to add g = gs*Rearth*Rearth/( (y+Rearth)*(y+Rearth) ); to calculate the gravity at height y as experienced by the rocket's position.
hint: remember to declare all variables you come up with like Rearth initial value is 6.37E6 metre, gs initial value is 9.81 m/s^2, g gravity at the height y.
Rearth initial value is 6.37E6 or 6.37x10^6 metre where E stands for exponential like x10^6
add a bar to display the value of g so that you can make sense if the calculation is correctly executed.


Task 6: model the temperature of air as y increases.
// formula given is T = T0 − L*y 
// where T0 = Temperatureo = 288 K is the temperature at sea level 
//where L is the “temperature lapse rate” (L = 0.0065 Kelvin per meter).
// when y reach what height it will be zero K ?
// in real life, 0 K cannot be reached in outer-space, it is about a bit higher say, 0.0065 K

can you design your logic codes to be something like this?
if (y<44307 br=""> Temperature= Temperatureo- L*y;
}
else if (y>44307){
Temperature=0.0065;
}

if (y<44307 br="">
 Temperature= Temperatureo- L*y;
}
else if (y>44307){
  Temperature=0.0065;
                           }

more to come!


photo gallery