A student uses a bottle opener to find that a force of 15 N must be exerted to lift a cap 1.4mm. The opener has a velocity ratio of 16 and efficiency of 90%

Question

(a) What is the mechanical advantage of the opener?
(b) What force is applied to the bottle cap?
(c) How far does the handle of the opener move?

Answer 1

The velocity ratio is 16, so the distance that the hand moves the bottle opener is
0.0015 m x 16 = .0.024 m. The energy expended lifting the cap is
E = (0.024 m)(15 N) = 0.36 J

(a) The mechanical advantage is the ratio of the force applied to the cap to the force applied to the opener. That equals 0.9 x 16 = 14.4

(b) The force applied to the cap is 0.9 * 16 * 15 N = 2160 N

(c) Multiply the velocity ratio (16) by the distance that the cap moves.

Answer 2

in part (b) you have considered force applied to be load shouldn't it be the effort put in to open the bottle.
Hence making it 15/0.9*16

Answer 3

No, the force applied to the bottle cap gets reduced by the efficiency factor, 0.9. However I did the multiplication incorrectly. It should be 216 N