Определить, как изменяется величина тормозной силы и время торможения в зависимости от скорости

Private Sub Command1_click()
 
Dim x0 As Single, dx As Single, xk As Single
Dim S As Single, m As Single, x As Single
Dim f As Single, t As Single
 
S = InputBox("ВВести S")
m = InputBox("ВВести m")
x0 = InputBox("ВВести V начальное")
dx = InputBox("ВВести d")
xk = InputBox("ВВести V конечное")
 
List1.AddItem "V      f      t"
 
For x = x0 To xk + dx / 2 Step dx
 
f = (x ^ 2) * m / 2 * S And t = 2 * x / t
 
 
'[выделено красным]
List1.AddItem "Format(x, "0.00") &" "
             & "Format(f, "0.00")" '[выделено красным]
              
 
Next
End Sub

List1.AddItem "Format(x, "0.00") & " " _
 & "Format(f, "0.00")" '1 - знак конкатенации д.б. окружен пробелами, 2 - строка переносится пробелом и знаком подчеркивания.

List1.AddItem Format(x, "0.00") & " " &  Format(f, "0.00")

Private Sub Command1_click()
 
Dim x0 As Single, dx As Single, xk As Single, x As Single
Dim y0 As Single, dy As Single, yk As Single, y As Single
Dim de As Single, v As Single, v0 As Single, R As Single, pi As Single
 
x0 = InputBox("Ââåñòè L íà÷àëüíîå")
dx = InputBox("Ââåñòè øàã L")
xk = InputBox("Ââåñòè L êîíå÷íîå")
R = InputBox("Ââåñòè R")
y0 = InputBox("Ââåñòè C íà÷àëüíîå")
dy = InputBox("Ââåñòè øàã C")
yk = InputBox("Ââåñòè C êîíå÷íîå")
 
pi = 3.14
 
List1.AddItem "L      C      v      v0      delta"
 
For x = x0 To xk Step dx
For y = y0 To yk Step dy
 
v = 1 / (2 * pi) * Sqr(1 / x * y - (R / 2 * y) ^ 2) {тут программа ругается}
v0 = 1 / (2 * pi * Sqr(l * c))
de = v - v
List1.AddItem Format(x, "###.####") & "    " & Format(y, "###.####") & "    " & Format(v, "###.####") & "    " & Format(v0, "###.####") & "    " & Format(de, "###.####")
 
Next y
Next x
 
End Sub