Diagram (b) is a free-body force diagram for the cupboard. *State the magnitude of force Y.

*Explain why forces X and P must have equal magnitude.

*Calculate the moment of the weight of the cupboard about a point A.
Moment=?

*Calculate the value of force X when h=0.60 m.
Force X=?

*In principle the fixing screws could be positioned anywhere between point A and the top of the
cupboard. Sketch a graph to show how the size of force X would depend on h for values of h from
zero up to 0.60 m.

(*) Mark is qustions.

Athin electrical heater is inserted between a long circular rod and a concentric tube with inner and outer radii of 20 and 40 mm. the rod (a) has a thermal conductivity of ka = 0.15 w/(m*k), while the tube (b) has a thermal conductivity of kb = 0.8 w/(m*k) and its outer surface is subjected to convection with a fluid of temperature t= -15°c and heat transfer coefficient 60 w/(m2 *k). the thermal contact resistance between the cylinder surfaces and the heater is negligible. (a) determine the electrical power per unit length of the cylinders (w/m) that is required to maintain the outer surface of cylinder b at 15°c. (b) what is the temperature at the center of cylinder a?