journal of science
education
Classroom
In this section of Resonance, we invite
readers to pose questions likely to be raised in a classroom situation.
We may suggest strategies for dealing with them, or invite responses,
or both. “Classroom” is equally a forum for raising broader
issues and sharing personal experiences and viewpoints on matters related
to teaching and learning science.
Scalars and Vectors in Physics – I
Scalar and vector quantities are ubiquitous in physics. However, most physics texts at the undergraduate level provide only a brief description of their nature. This creates confusion for many: all magnitudes are scalars and any physical quantity with magnitude and direction is defined as vector. The true test of a scalar or vector quantity comes by testing its nature under Galilean transformations, directed line segment, parallelogram or triangular law of addition. This article covers the nature of scalars and vectors that is appropriate for the undergraduate level. Lorentz scalars and vectors in four-dimensional space will be discussed in the next part.
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Learning Earthquake Design and Construction
5. What are the Seismic Effects on Structures?
6. How Architectural Features Affect Buildings During Earthquakes
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Earthquake causes shaking of the ground. So a building resting on it will experience motion at its base. From Newton’s First Law of Motion, even though the base of the building moves with the ground, the roof has a tendency to stay in its original position. But since the walls and columns are connected to it, they drag the roof along with them. This is much like the situation that you are faced with when the bus you are standing in suddenly starts; your feet move with the bus, but your upper body tends to stay back making you fall backwards!! This tendency to continue to remain in the previous position is known as inertia. In the building, since the walls or columns are flexible, the motion of the roof is different from that of the ground.
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Importance of Architectural Features
The behaviour of a building during earthquakes depends critically on its overall shape, size and geometry, in addition to how the earthquake forces are carried to the ground. Hence, at the planning stage itself, architects and structural engineers must work together to ensure that the unfavourable features are
avoided and a good building configuration is chosen.The importance of the configuration of a building was aptly summarised by Late Henry Degenkolb, a noted Earthquake Engineer of USA, as:
“If we have a poor configuration to start with, all the engineer can do is to provide a band-aid – improve a basically poor solution as best as he can. Conversely, if we start-off with a good configuration and reasonable framing system, even a poor engineer cannot harm its ultimate performance too much.”
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