FEMA Ch. 4

Question 1

What is Newton’s Second Law of Motion

Answer 1

F=MA, F, force equals mass, M, multiplied by acceleration, A.

Question 2

Mass, in terms of a building, is equal to what?

Answer 2

Mass is the equivalent (at the ground level) to the weight of the building.

Question 3

Define acceleration and it’s unit of measurement

Answer 3

Acceleration is the rate of change of the velocity of the waves setting the building in motion. It determines the percentage of the building mass or weight that must be dealt with as a horizontal force. It is measured in terms of the acceleration due to gravity or g.

Question 4

Duration & Acceleration

Answer 4

The number of cycles of moderate acceleration, sustained over time, can be much more difficult for a building to withstand than a single much larger peak. Continued shaking weakens a building structure and reduces its resistance to earthquake damage.

Question 5

Bracketed Duration

Answer 5

The shaking duration above a certain threshold acceleration value, commonly taken as .05g, and is defined as the time between the first and last peaks of motion that exceeds this threshold value.

Question 6

Velocity

Answer 6

Measured in inches or centimeters per second, is the rate of motion of the seismic waves as they travel through the earth.