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Unformatted text preview: PHY 2053, Section 3794, Fall 2009, Quiz 1
Use scientiﬁc notation and pay attention to signiﬁcant ﬁgures.
1.
a) A rectangle has one side of 10.2cm and one side which is 1ft,2in long. What is its
area in cm2 ?
1ft,2in = 14in = 14 × 2.54cm = 35.56cm, so area = 35.56 × 10.2 = 362.712cm2 . Note:
could truncate to 362.7cm2 . Using scientiﬁc notation and keeping only 2 signiﬁcant ﬁgures
(14in is only known to 2 signiﬁcant ﬁgures) gives area = 3.6 × 102 cm2 .
b) You can spread oil paint over the surface at the rate of 0.046 cm2 /sec. How many
minutes does it take for you to cover the surface?
time = 362.7/0.046 sec = 7885. sec =7885/60 min = 1.3 × 102 min (to 2 sig. ﬁgs). Note: use
your intermediate result from part a) with more than 2 sig. ﬁgs! 2.
a) The hypotenuse of a rightangled triangle has length 6.5cm and one side is 6.0cm long.
How long is the other side?
√
√
Using Pythagoras we have b = c2 − a2 = 6.52 − 6.02 cm = 2.5cm. Note: only 2 sig. ﬁgs.
b) The sides of a rightangled triangle are 1.5in, 2.0in and 2.5in. What is the tan of the
smallest angle inside the triangle?
The smallest angle is opposite the smallest side. The longest side is the hypotenuse, so tan
of the smallest angle is 1.5/2.0 = 0.75 = 7.5 × 10−1 in scientiﬁc notation. Note: tan is
dimensionless. ...
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This note was uploaded on 12/15/2011 for the course PHY 2053 taught by Professor Buchler during the Fall '06 term at University of Florida.
 Fall '06
 Buchler
 Physics

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