Multiplication and Division using Significant Figures
Rule: In multiplication and
division, the result may have no more significant figures than the factor with
the fewest number of significant figures.
example: 2.52 m x 1.000
424 3 m = 2.521 069 236 m2 but must be recorded
as 2.52 m2 (3 sig figs)
example: 7540 m x 1.3 m
= 0902.000 m2 but must be recorded as 9800 m2
(only 2 sig figs)
Rule: When adding and subtracting
numbers that come from measurements, arrange the numbers in columnar
form. The final answer can contain only as many decimal places as found
in the measurement with the fewest number of decimal places.
example: 134.050 m
+ 1.23 m =
134.050 m
+ 1.23 m
135.28 m (2 decimal places)
Directions: Perform all the operations using your
calculator and record the answer with the proper number of significant
figures. See Mr. Jones for answers.
1.
(3.4617 E 2) (5.61 E -4)
(9.87
E 5) (3.1) (1.171 E 4)
2.
(3.52164 E 2) (3.1741 E 5)
(8.22 E 7) (4.65217 E -3) (9.711 E 4)
3.
(1.8741 E 11)
(5.6 E 4) (2.173 E 8)
4.
(1.745 E -2) (9.51 E -7)
(16.21) (9.346 E -10)
5.
(3.4721 E 5)
(5.6145 E 7) (9.5 E 1)
Word Problems using Significant Figures
Directions: Solve the
following word problems and record the answer using the proper number of sig
figs. Use 3.1416 for p.
See Mr. Jones for answers.
1. The volume of a cylinder is:
V = p
r2 L
What is the volume of a cylinder that has a radius of 0.0631 m and a
length of 2.0 m?
2.
The 100 sheets of a textbook measure 0.02375 m.
What is the thickness of only 1 of those sheets?
3.
formula: t
= d/V
How
long does it take light traveling at 2.99793 E 8 m/s to travel across a room that
is 6.2 m long?
4.
formula: ac
=
4p
r/T2
Find
the centripetal acceleration (ac)
when the radius is 1.261 m and the period (T)
is 0.64 s.
5.
formula: d
= 1/2 a t2
What
is the distance traveled by a body from rest when the gravitational
acceleration (a) is 9.80665 m/s2 and the fall time (t) is
13.29 s?
6. I massed 150 tacks. The
total mass was 10.35 g. What is
the mass of a single tack?
