Q5. A man uses a crowbar of length 1.5 m to raise a load of 75 kgf by putting a sharp edge below the bar at distace of 1 m from his hand. (a) Draw a diagram of the arrangement showing the fulcrum (F), load (L) and effort (E) with their directions, (b) State the kind of leaver. (c) Calculate : (i) load arm, (ii) effort arm, (iii) mechanical advantage, and (iv) the effort needed.
Ans. (b) class I (c) (i) 0.5 m (ii) 1.0 m (iii) 2 (iv) 37.5 kgf.
Q6. A pair of scissors is used to cut a piece of a cloth by keeping it at a distance of 8-0 cm from its rivet and applying an effort of 10 kgf by fingers at a distance of 2.0 cm from the rivet.
(a) Find : (i) the mechanical advantage of scissors, and (ii) the load offered by the cloth.
(b) How does the pair of scissors act : as a force multiplier or as a speed multiplier?
Ans. (a) (i) 0.25 (ii) 2.5 kgf. (b) Speed multiplier
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