Two train whistles, and , each have a frequency of 392 hz. is stationary and is moving toward the right (away from ) at a speed of 35.0 m/s. a listener is between the two whistles and is moving toward the right with a speed of 15.0 m/s no wind is blowing. (a) what is the frequency from as heard by the listener? (b) what is the frequency from as heard by the listener? (c) what is the beat frequency detected by the listener?

Copper has free electrons per cubic meter. a 71.0-cm length of 12-gauge copper wire that is 2.05 mm in diameter carries 4.85 a of current. (a) how much time does it take for an electron to travel the length of the wire? (b) repeat part (a) for 6-gauge copper wire (diameter 4.12 mm) of the same length that carries the same current. (c) generally speaking, how does changing the diameter of a wire that carries a given amount of current affect the drift velocity of the electrons in the wire?

The boy of mass 30 kg is at r1= 2 meters from the fulcrum. of the girl is 45 kg, at what r2 must she sit so that they are balanced ?

As a pendulum bob swings back and forth several times, the maximum height it reaches becomes less and less. this is because more and more of the pendulum bob's energy is being transformed into a. heat energy b. kinetic energy c. potential energy d. kinetic energy and potential energy