At 11:00 AM on September 7. 2001, more than one million British school children

Question

At 11:00 AM on September 7. 2001, more than one million British school children jumped up and down for one minute to Simulate an earthquake. Find the energy stored In the children's bodies that was converted into Internal energy In the ground and their bodies and propagated Into the ground by seismic waves during the experiment. Assume that 1 150 000 children of average mass 39.0 kg Jurip 10 times each, raising their centers of mass by 20.0 cm each time and briefly resting between one Jump and the next. Of the energy that propagated into the ground, most produced high-frequency "microtrernor" vibrations that were rapidly damped and did not travel far. Assume 0.01% of the total energy was carried away by long-range seismic waves. The magnitude of an earthquake on the Richter scale is given by M = log E - 4.8/1.5 where E is the seismic wave energy In joules. Accord.ng to this model, what Is the magnitude of the demonstration quake? Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully on the Richter scale

Explanation / Answer

a) energy of 1 student in 1 jump = mgh = 39 x 9.8 x 0.2 = 76.44 J

total energy = 1 150 000 x 76.44 x 10 = 8.79 x 10^8 J

b) E = 0.01% of total energy

    = 0.01 x 8.79 x 10^8 /100 = 87906 J

M = log(87906) - 4.8 / 1.5

M = 0.096

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.