A trumpet player on a moving railroad flatcar moves toward a second trumpet player standing alongside the track while both play a 330 Hz note. The sound waves heard by a stationary observer between the two players have a beat frequency of 5.0 beats/s. What is the flatcar's speed? (The speed of sound in the air is 343 m/s.)

The temperature in gavin's oven is a sinusoidal function of time. gavin sets his oven so that it has a maximum temperature of 280°f and a minimum temperature of 240°. once the temperature hits 280°, it takes 20 minutes before it is 280° again. gavin's cake needs to be in the oven for 30 minutes at temperatures at or above 270°. he puts the cake into the oven when it is at 260° and rising. how long will gavin need to leave the cake in the oven? (round your answer to the nearest minute.)