(1),x1+x2=s2=vt2+at²/2=v·4T+a(4T)²/2 ···①
x1=s1=vt1+at²/2=v·2T+a(2T)²/2 ···②
①-2x②,得,s2-s1=(x2+x1)-2·x1=a·4T²
∴a=(x2-x1)/(4T²).
(2),F阻力=m(g-a)=m【g-(x2-x1)/(4T²)】.
解毕.
(1),x1+x2=s2=vt2+at²/2=v·4T+a(4T)²/2 ···①
x1=s1=vt1+at²/2=v·2T+a(2T)²/2 ···②
①-2x②,得,s2-s1=(x2+x1)-2·x1=a·4T²
∴a=(x2-x1)/(4T²).
(2),F阻力=m(g-a)=m【g-(x2-x1)/(4T²)】.
解毕.