6. Mechanical advantage of a machine.
Exercises
1. Give six examples of levers you use.
2. Fig. 88a represents a pair of paper shears, 88b a pair of tinner's shears. Which has the greater mechanical advantage? Why? Explain why each has the most effective shape for its particular work.
Fig. 88.—(a) Paper shears. (b) Tinner's shears.
3. Find examples of levers in a sewing machine.
4. What would result if, in Art. 122, the 100 g. weight were put 25 cm. from O and the 50 g. weight 45 cm. from O? Why? Explain using principle of moments.
5. How is the lever principle applied in rowing a boat?
6. When you cut cardboard with shears, why do you open them wide and cut near the pivot?