Suppose a train sounding its horn is moving at 30.0 m/s in s…

Suppose a train sounding its horn is moving at 30.0 m/s in still air on a day when the speed of sound is 340.0 m/s. As the train passes the platform, on which you stand (moving away from you), you hear it with a frequency of 167 Hz. Which frequency does an observer on the train hear?

  A mass m = 8.0 kg is attached to a spring and allowed to h…

  A mass m = 8.0 kg is attached to a spring and allowed to hang in the Earth’s gravitational field. The spring stretches 2.5 cm before it reaches its equilibrium position (where the spring force balances gravity). If allowed to oscillate, what would be its frequency?  

A mass m = 7.0 kg is attached to a spring and allowed to han…

A mass m = 7.0 kg is attached to a spring and allowed to hang in the Earth’s gravitational field. The spring stretches 4.4 cm before it reaches its equilibrium position (where the spring force balances gravity). If allowed to oscillate, what would be its period?