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timnswede
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Homework Statement
A clock has a 20 cm minute hand. From the 6 PM mark to the 9 PM mark, for the tip of the minute hand, calculate:
a. the displacement vector in unit-vector notation.
b. the average velocity vector in unit-vector notation.
c. the average acceleration vector in unit-vector notation.
d. calculate the magnitude and direction of the average acceleration vector.
2. The attempt at a solution
a. I named my 6 PM vector B and my 9 PM vector A. A=-20i and B=-20j. A-B=C(the displacement vector) which equals -20i+20j
b. V=(-20i+20j)/15min= -4/3i+4/3j cm/min
c. Vi=Vf=40∏/60=2∏/3
Vi=-2∏/3i
Vf= 2∏/3j
Aave= (2∏/3i+2∏/3j)/15min = 2∏/45i+2∏/45j cm/min^2
d. √((2∏/45)^2)+(2∏/45)^2) = .197 cm
tanΘ=2∏/45/2∏/45 = 45°
I am not sure if I did b, c, or d right.
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