1- On a large lake without waves, how far from shore is a sailboat when the top of its 15m mast disappears from the view a person whose eye height is 2 m
above the water’s edge. Explain using your own words how you get your answer

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