'monkey hunting	
'theory of momentum	
	
SetVersion(0.9)	
mathgraph on	
'/-----------screen adjustment---------------------	
tscreen(300,150) : twposition(10,500) : gwposition(10,10)	
opengscreen(360,480)	
window(-5,-100)-(145,100)	
line(-5,0)-(145,0) : line(0,-100)-(0,100)	
	
'-----------initial conditon-----------------------	
g=9.81 : dt=0.01 : a=-g      	
vx2=0  : vy2=0                {free fall}	
x1=0   : y1=0                 	
data   2,  1, 30,45, 60, 1.0	
read  m1, m2, v1, ang, x2, e	
	
glocate (5,-15):gprint "angle="	
glocate (33,-15):gprint "�K"	
glocate (25,-15):gt$=str$(ang):gprint gt$	
ang=ang*pi/180                {degree ==> radian }	
y2=x2*tan(ang)   :m=x2 :n=y2        {height of "monkey"} 	
vx1=v1*cos(ang) : vy1=v1*sin(ang)	
r1=m1/m2  	
                    	
data   2, 1, 9 	
read   c,c1,c2	
line(0,0)-(x2,y2),c	
glocate (5,-5):gprint "m1="	
glocate (20,-5):gt$=str$(m1):gprint gt$	
glocate (5,-10):gprint "v1="	
glocate (20,-10):gt$=str$(v1):gprint gt$	
	
glocate (x2+5,y2+10):gprint "m2="	
glocate (x2+15,y2+10):gt$=str$(m2):gprint gt$	
glocate (x2+5,y2+5):gprint "x2="	
glocate (x2+15,y2+5):gt$=str$(x2):gprint gt$	
glocate (x2+5,y2):gprint "y2="	
glocate (x2+15,y2):gt$=str$(y2):gprint gt$	
	
'/-----------shot!---------------------------------	
dvx1=0 : dvy1=a*(dt/2)	
dvx2=0 : dvy2=a*(dt/2)	
*shot	
'bullet	
gosub *Eular1	
'falling monkey	
gosub *Eular2	
circle(x1,y1),r1,c1,,,,,f : circle(x2,y2),1,c2,,,,,f	
if x1<x2 then goto *shot	
	
'/--------collision!--------------------------------	
beep	
glocate (5,30):gprint "e="	
glocate (10,30):gt$=str$(e):gprint gt$	
	
print "x1,y1=" : print x1, y1	
print "x2,y2=" : print x2, y2
yc=n-g*m^2/(2*v1^2*(cos(ang))^2) : print "yc=",yc
	
px=m1*vx1+m2*vx2 : py=m1*vy1+m2*vy2	
dvx=vx1-vx2      : dvy=vy1-vy2	
'bullet	
vx1=(px-m2*dvx*e)/(m1+m2) : vy1=(py-m2*dvy*e)/(m1+m2)	
'falling monkey	
vx2=(px+m1*dvx*e)/(m1+m2) : vy2=(py+m1*dvy*e)/(m1+m2)	
	
dvx1=0 : dvy1=a*(dt/2)	
dvx2=0 : dvy2=a*(dt/2)	
*collision	
'bullet     	
gosub *Eular1	
'falling monkey 	
gosub *Eular2 	
	
circle(x1,y1),r1,c1,,,,,f: circle(x2,y2),1,c2,,,,,f	
if (y1>-100) or (y2>-100) then goto *collision	
end	
	
'----------sub(Eular method)--------------	
*Eular1	
vx1=vx1+dvx1   : vy1=vy1+dvy1	
dx1=vx1*dt     : dy1=vy1*dt	
x1 =x1+dx1     : y1 =y1+dy1	
dvx1=0         : dvy1=a*dt	
return	
	
*Eular2 	
vx2=vx2+dvx2 : vy2=vy2+dvy2 	
dx2=vx2*dt   : dy2=vy2*dt  	
x2=x2+dx2    : y2 =y2+dy2	
dvx2=0       : dvy2=a*dt	
return