learn-physics-examples 0.5 → 0.5.0.1

raw patch · 2 files changed

+78/−1 lines, 2 files

Files

• learn-physics-examples.cabal +1/−1
• src/Projectile.hs +77/−0

@@ -1,5 +1,5 @@ Name:                learn-physics-examples-Version:             0.5+Version:             0.5.0.1 Stability:           Experimental Synopsis:            examples for learn-physics Description:         Executables that use the learn-physics library.

@@ -0,0 +1,77 @@+{-# OPTIONS_GHC -Wall #-}++module Main where++import Graphics.Gnuplot.Simple+import Physics.Learn++--type StateTuple = (Double,Vec,Vec)+--type AccelerationFunction = StateTuple -> Vec++--eulerCromerSolution :: Double -> AccelerationFunction+--                    -> StateTuple -> StateTuple+--eulerCromerSolution++-- vertical direction is y direction+earthSurfaceGravity :: OneParticleAccelerationFunction+earthSurfaceGravity _state = vec 0 (-g) 0++g :: Double+g = 9.81++projectileTuples :: Double -> Double+                 -> OneParticleAccelerationFunction+                 -> [OneParticleSystemState]+projectileTuples v0 theta af+    = oneParticleRungeKuttaSolution af 0.01+      (0, St (cart 0 0 0) (vec vx0 vy0 0))+      where+        vx0 = v0 * cos theta+        vy0 = v0 * sin theta++yCoord :: Position -> Double+yCoord r = y+    where+      (_,y,_) = cartesianCoordinates r++inAir :: [OneParticleSystemState] -> [OneParticleSystemState]+inAir = takeWhile (\(_,St r _) -> yCoord r >= 0)++initialProjState :: Double -> Double -> OneParticleSystemState+initialProjState v0 theta+    = (0, St (cart 0 0 0) (vec vx0 vy0 0))+      where+        vx0 = v0 * cos theta+        vy0 = v0 * sin theta++-- air resistance quadratic in the speed+surfaceGravityAirResistance :: Double -> Double+                            -> OneParticleAccelerationFunction+surfaceGravityAirResistance m b (_t,St _r v)+    = netForce ^/ m+      where+        netForce      = gravity ^+^ airResistance+        gravity       = vec 0 (-m * g) 0+        airResistance = ((-b) * magnitude v) *^ v++trajectory :: [OneParticleSystemState] -> [(Double,Double)]+trajectory sts = [(x,y) | (_,St r _) <- sts, let (x,y,_) = cartesianCoordinates r]++traj :: Double -> [(Double,Double)]+traj b = trajectory $ inAir+         $ oneParticleRungeKuttaSolution+               (surfaceGravityAirResistance 2 b)+               0.01+               (initialProjState 30 (pi/6))++main :: IO ()+main = plotPathsStyle+       [Title "Trajectories of 2-kg object, initial speed 30 m/s, angle 30 degrees"+       ,XLabel "Range (m)"+       ,YLabel "Height (m)"+       ,PNG "learn-physics-Projectile.png"+       ] [(defaultStyle {lineSpec = CustomStyle [LineTitle "No air resistance"]}, traj 0)+         ,(defaultStyle {lineSpec = CustomStyle [LineTitle "Drag 0.01 kg/m"]}, traj 0.01)+         ,(defaultStyle {lineSpec = CustomStyle [LineTitle "Drag 0.02 kg/m"]}, traj 0.02)+         ] >> putStrLn "output sent to file learn-physics-Projectile.png"+