Manipulate[
 Labeled[Panel[((a) (c) + (b) (d))], "Work done on object =", Left, 
   LabelStyle -> Purple, ImageSize -> {400, 100}]
  Graphics[ {
    Arrowheads[.1],
    {RGBColor[1, 0, 0], Thickness[.02], 
     Dynamic[Arrow[{{0, 0}, {a, b}}]]},
    {RGBColor[0, 0, 1], Thickness[.02], 
     Dynamic[Arrow[{{0, 0}, {c, d}}]]},
    Locator[Dynamic[{a, b}], ImageSize -> 10],
    Locator[Dynamic[{c, d}], ImageSize -> 10], 
    PlotRange -> {{-5, 5}, {-5, 5}}, ImageSize -> {400, 200}
    }],
 {{a, 1, "Displacement- X"}, -5, 5}, {{b, 0, "Displacement- Y"}, -5, 
  5}, Delimiter, {{c, 1, "Force- X"}, -5, 
  5}, {{d, 1, "Force- Y"}, -5, 5},  Paneled -> True, 
 FrameLabel -> {{"", ""}, {"", 
    "Dot Product of Displacement and Force Vectors"}},  
 ControlPlacement -> Bottom]