(a) State the conditions of equilibrium for a number of coplanar parallel forces.

(b) A metre rule is found to balance horizontally at the 48 cm mark. When a body of mass 60 g is suspended at the 6 cm mark, the balance point is found to be at the 30 cm mark. Calculate the;

(i) mass of the metre rule;

(ii) distance of the balance point from the zero end, if the body were moved to the 13 cm mark.

(c) a man pulls up a box of mass 70 kg using an inclined plane of effective length 5 m unto a platform 2.5 m high at a uniform speed. If the frictional force between the box and the plane is 1000 N;

(i) draw a diagram to illustrate all the forces acting on the box while in motion;

(ii) calculate the I. minimum effort applied in pulling up the box; II. velocity ratio of the plane, if it is inclined at 30° to the horizontal; Ill. force ratio of the plane.