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Chapter Nine - Tricks and Time Savers 61A direct solution can be obtained on your slide rule by reversing the slide.Remove it and switch ends, with the same side facing you. Your slide is nowupside down.Cursor to 4 on DSlide to 6 on C at cursorCursor to 9 on CAnswer: 2.67 on D atcursorPendulum oscillationsCursor to 375 on DSlide to pendulum length in inches on B at cursorAnswer on D at index of C, in oscillations per minuteTry: How many oscillations per minute will a 39” long pendulum make?Cursor to 375 on DSlide to 39 on B at cursor (Note: 39 is the second section of the B scale)What if you want your pendulum to oscillate only 30 times per minute? Howlong would it need to be?Cursor to 375 on DSlide to 30 on D at left index of CHow about 120 times per minute?Cursor to 375 on DSlide to 120 on D at left index of CAnswer: 60 oscillationsper minute on D at rightindex of C ... one persecond.Answer: 156” on B atcursor.Answer: 9.8” on B atcursor.It is quite interesting to see the drastic length change required to double orhalve the oscillation rate.Useful constantsDiameter of circle =Side of inscribed square= diagonal of square = square root of 2side of squarePounds per square inch =Feet of waterNote: Once these ratios are set up on your slide rule, you can, of course,use them to find any circle and its inscribed square ... or the pressure from acolumn of water of any height by moving only the cursor. This is true of anyratio because of the “parallel” nature of the slide rule as a calculating device.