It Is Possible to Hear an Approaching Train Before You

question 7

Multiple Choice

It is possible to hear an approaching train before you can see it by listening to the sound wave through the track. If the elastic modulus is 2.0 × 10¹¹ N/m² and the density of steel is 7.8 × 10³ kg/m³, approximately how many times faster is the speed of sound in the track than in air? (v_air ≈ 340 m/s.)

• A) 20
• B) 5
• C) 10
• D) 15
• E) 25

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Definitions:

Belief in God

Belief in God encompasses faith or conviction in the existence of a supreme deity or deities, central to many religious traditions.

Irrational

Going against the rules of reason. (Not the same as nonrational, such as when we say that worms and fish are “not rational animals.”) Only rational (that is, thinking, planning, calculating) creatures can be irrational.

Problem of Evil

A philosophical dilemma concerning how to reconcile the existence of evil with an omnipotent, omnibenevolent, and omniscient God.

Theodicies

Justifications of God's goodness and omnipotence in the face of the existence of evil.