San Francisco State University
Department of Geosciences
Name _______________________
Metr 201
Homework #2: Acceleration and Velocity: Unit Conversions (100 pts) (Key)
(Due Tuesday 16 April 2013)
Please answer on back or on separate sheets. You may know the answers to these
questions without performing unit conversions. However, the purpose of this
homework is for you to do those conversions.
1. What are the units of acceleration in the mks system? (5 points)
The unit of acceleration in the mks (meters, kilograms, seconds) system is meters/sec2 or m s-­‐2 2. The acceleration of gravity in the English system is 32 ft/sec2. What is the
value of the acceleration of gravity in the mks system? (Hint: 2.54 cm/in).
(20 points)
32 ft
12 in
2.54 cm
m
m
X
X
X
= 9.8 2
2
sec
foot
in
100 cm
sec
or 9.8 m s-­‐2 3. What are the units of acceleration in the cgs system? (5 points)
The unit of acceleration in the cgs (centimeters, grams, seconds) system is centimeters/sec2 or cm s-­‐2 4. Convert meters/second to statute miles/hour. (Hint: 2.54 cm/in; Statute
Mile=5280 ft). (20 points)
m
100 cm
in
ft
mile
3600 sec
miles
X
X
X
X
X
= 2.24
= 2.24 miles h −1
sec
m
2.54 cm
12 in 5280 ft
hr
hr
5. The units for the horizontal wind are meters/second. The synoptic scale
vertical wind is two orders of magnitude smaller than the horizontal wind.
What are the cgs units of the synoptic scale vertical wind? (20 points)
m
1
0.01 m cm
X 2 =
=
sec
10
sec
sec
or cm s-­‐1 6. In the severest thunderstorms,at the mesoscale, vertical velocities at the
equilibrium level (explained in class) are on the order of 40 meters per
second. Convert that to miles per hour (Hint: 2.54 cm/in; Statute Mile=5280
ft). (20 points)
40m
100 cm
in
ft
mile
miles
X
X
X
X
= 89.6
= 89.6 miles h −1
sec
m
2.54 cm
12 in 5280 ft
hr