A box of mass $m$ moves down a slope of length $l$ while opposing a frictional force $F$. It drops through a vertical height $d$. As the box moves down the slope, gravitational potential energy is lost and work is done against friction. Which row shows the loss in gravitational potential energy and the work done against friction?
- Aloss in gravitational potential energy: $mgd$; work done against friction: $Fl$
- Bloss in gravitational potential energy: $mgd$; work done against friction: $Fd$
- Closs in gravitational potential energy: $mgl$; work done against friction: $Fl$
- Dloss in gravitational potential energy: $mgl$; work done against friction: $Fd$