State the class of levers and the relative positions of load (L), effort (E) and fulcrum (F) in

(a) a bottle opener, and

(b) sugar tongs.

Indicate the positions of load L, effort E and fulcrum F in the forearm shown below. Name the class of lever.

Explain why scissors for cutting cloth may have blades longer than the handles, but shears for cutting metals have short blades and long handles.

Figure shows a uniform metre rule of weight W supported on a fulcrum at the 60 cm mark by applying the effort E at the 90 cm mark.

(a) State with reasons whether the weight W of the rule is greater than, less than or equal to the effort E.

(b) Find the mechanical advantage in an ideal case.