Batter boards serve what purpose? a. they serve as reference marks for builders when foundation are being excavated and formed. b. they carpenters cut hip rafters in complex roof framing. c. they brace foundation walls against cave-ins. d. they prevent the collapse of heavy timber beams or trusses in the event of fire. e. they in temporarily bracing wood light frame buildings against lateral loads (e. g., wind).

Afour cylinder four-stroke in-line engine has a stroke of 160mm, connecting rod length of 150mm, a reciprocating mass of 3kg and its firing order is 1-3-4-2. the spacing between cylinders is 100mm. i. show that the engine is in balance with regard to the primary inertia forces and primary 3. a and secondary inertia couples. li determine the out of balance secondary inertia force ii. propose ways of balancing this out of balance force and discuss the challenges that will arise