Physics
590 Homework
Week 1,
Homework 1
Prob.
1.1.1
The age
of the universe is
about 14 billion years. Assuming one significant figure, write the
age of
the universe in (a)
10,000,000years,
(b)
1x10^8yr x 365 day/yr
x 24 hr/day x 60 min/hr x 60 sec/min=
3x10^15
seconds.
Prob.
1.1.2
How
many significant
digits do each of the following numbers have: (a) 2142 (4), (b) 81.60
(4), (c)
7.63 (3), (d) 0.03 (1), (e) 0.0086 (2), (f) 3236 (4), and (g) 8700 (2)?
Prob.
1.1.3
Write
the following
numbers in powers of ten notation: (a) 1,156 (1.156 x 10^3), (b)21.8
(2.18 x
10^1, (c) 0.0068 (6.8 x 10^-3), (d) 27.635 (2.7635 x 10^1), (e)
0.219 (2.19 x 10^-1, and (f) 22
(2.2 x 10^1).
Prob.
1.1.4
Write
out the following
numbers in regular form with a decimal point and the correct number
of
zeros: (a) 8.69 × 104 , (b) 7.1
× 103, (c) 6.6
× 10−1, (d) 8.76
× 102, and (e) 8.62
× 10−5.
a)
86,900 b) 7,100
c) 0.66 d)876.
e) 0.0000862
Prob.
1.1.5
What is
the percent
uncertainty for the measurement given as 1.28 m?
.01/1.28
x 100%= .8%
Prob.
1.1.6
Multiply
2.079 × 102 by 0.072
× 10−1, taking into account
significant figures.
(2.079)(0.072)(10^2)(10^-1)
(
1.479
)( 10^1 )= 15
Prob.
1.1.7
What is
the area, and its
approximate uncertainty, of a circle of radius 3.8
× 104 cm?
2π(3.8
x 10^4)= 2.4 x 10^5
Prob.
1.1.8
Write
the following as
standard numbers (with decimal points in the correct position) in
units
of meters,
kilograms, or seconds as appropriate: (a) 286.6 mm (0.2866m), (b) 85 μg
(0.000085 g), (c) 760 mg
(0.76 g), (d) 60.0 picoseconds (0.0000000000600s), (e) 22.5 femtometers
(0.0000000000000225m),
and (f)
2.50 gigagrams
(2,500,000,000 g)
Prob.
1.1.9
What is
the conversion
factor between (a) ft2 and yd2 and
(b) ft2 and m2?
a) 9
ft^2 = 1yd^2 b) (3.281)^2 ft^2 = m^2
10.765 ft^2 =
m^2
Prob.
1.1.10
Determine
the conversion
factor between (a) km/h and mi/h, (b) m/s and ft/s, and (c) km/h
and m/s.
a)1km/hr=
0.6214mi/hr
b)1m/s
= 3.281ft/s
c)
1km/hr x 1000m/km x
hr/60min x min/60s = .28 m/s