A train passes by an little boy at the depot. as is moves away from the boy at 65 m/s, the whistle emits a feaquency of 4500hz. what freaquency does the little boy hear as the train barrels off into the distance? speed of sound in air is 343 m/s

Acar is traveling at 53.0 mi/h on a horizontal highway. (a) if the coefficient of static friction between road and tires on a rainy day is 0.104, what is the minimum distance in which the car will stop?

Simon is writing a story about an astronaut whose spacecraft has been boarded by space pirates. the astronaut has her lucky penny in her hand behind her back as the space pirates break into the control room. she has just locked the controls so that the ship is accelerating in the direction of the control room’s ceiling. simon wants the astronaut to use the penny to hit a button on the control panel to turn off the lights and escape. the button is located a short distance behind and below the astronaut’s hands. how should simon use the theory of relativity to describe what the astronaut must do in order to hit the button?

Jenny wants to test the electrical conductivity of two substances dissolved in water. she is preparing the containers for the experiment. which factor is most important for her to control? a) volumes of the solutions b) appearance of the solutions c) temperatures of the solutions d) concentrations of the solutions