3-4+wells

Objectives: Daily Question Notes on UMC +Speed Tangential Speed Calculations Other UCM questions (HW??)

Daily Question: the Guests at a large table in a Chinese restaurant use a revolving tray, a lazy usan, to share the food dishes. How does the lazy Susan's motion differ from that of the passing dessert cart? Answer: the Dessert cart only moves in a straight line where as the lazy Susan doesn't move but can revolve around a single point. also the lazy Susan only have on rotational point where as the cart have 4(or 5).

Notes: tangential Speed -> is the speed of an object while it rotates around a circle. Calculations: V= Circumference/ T for 1 rotation Circumference= 2(Pi)r V= 2(Pi)/T for one rotation Ex: 2(Pi)(.373m)/13.29s= 2.34m/13.29s= .176m/s

More Notes: Frequency= # of rotations/ Time Ex: 5 rots/ 1 min or 5 rots/60s= .083 rots/s so to find time for one rotation you take your time/Freq. Ex: 60s/5rots= 12s More Examples: The Claw 2(Pi)6.0m/t But we don't know t yet so we use t=1/freq t=1/9 t=.11min (Note: its in minutes not seconds which means it turns 11% of the circle in one min) to convert into seconds .11(60)= 6.6s we now know t, so plug it in. 2(pi)6.0m/6.6s which equals.... 5.7m/s more examples are on page 3 of this unit... homework was page four in our unit which is fairly easy considering all you have to do is circle a,b,c,d, or e.