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6th Edition

Stewart + 5 others

Publisher: Cengage Learning

ISBN: 9780840068071

Chapter 2.3, Problem 44E

(a)

To determine

The time at which the earthquake first make the noticeable movements of the earth.

Expert Solution

The first noticeable movement took place after 5 seconds.

A graph is given which shows the vertical acceleration of the ground from an earthquake as measured by a seismograph.

Figure (1)

The acceleration is given on vertical axis and the time in seconds on horizontal axis.

From Figure (1), it is noticed that the acceleration of ground is there right after 5 seconds.

Therefore, the first noticeable movement took place after 5 seconds.

(b)

To determine

At what time the earthquake ended.

Expert Solution

The earthquake ended after 30 seconds.

A graph is given which shows the vertical acceleration of the ground from an earthquake as measured by a seismograph.

Figure (1)

From Figure (1), it is noticed that there is no acceleration of the ground after 30 seconds. It clearly means that the earthquake stopped after 30 seconds.

Therefore, the earthquake ended in 30 seconds.

(c)

To determine

At what time the earthquake had maximum intensity.

Expert Solution

The maximum intensity of the earthquake was reached after 17 seconds.

A graph is given which shows the vertical acceleration of the ground from an earthquake as measured by a seismograph.

Figure (1)

Locate the local maximum point to find the time at which earthquake had the maximum intensity.

The value
*f* if
*a* is near to *x*.

From the Figure (1), it is noticed that the value of acceleration is maximum between

The acceleration is more than

This is the point of local maximum.

Therefore, the maximum intensity of the earthquake was reached after 17 seconds.