Engineering Fundamentals: An Introduction to Engineering, 4th ed.c

8.5 Engineering Parameters Involving Length and Time 217

and the acceleration created by the force is referred to as theacceleration due to gravity(g). At the

surface of the earth, the value ofgis equal to 9.81 m/s

2

, or 32.2 ft /s

2

. In general, acceleration due
to gravity is a function of latitude and longitude, but for most practical engineering applications
near the surface of the earth the values of 9.81 m/s
2
or 32.2 ft /s
2
are sufficient.
Table 8.3 shows speed, acceleration, and the distance traveled by a falling object from the
roof of a high-rise building. We have neglected air resistance in our calculations. Note how the
distance traveled by the falling object and its velocity change with time.

TABLE 8.3 Speed, Acceleration, and Distance Traveled by

a Falling Object Neglecting the Air Resistance

Acceleration Speed of the Distance Traveled (m)

Time of the Object Falling Object

(seconds) (m/s^2 ) (m/s) (Vgt)

0 9.81 0 0

1 9.81 9.81 4.90

2 9.81 19.62 19.62

3 9.81 29.43 44.14

4 9.81 39.24 78.48

5 9.81 49.05 122.62

6 9.81 58.86 176.58

ad

1

2

g t^2 b

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