The siren of a police car at rest emits at a predominant frequency of 1980 hz. what frequency will you hear if you are at rest and the police car moves at 34.3.0m/s (a) toward you, and (b) away from you? explain

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

We put a force of 50n on an object and the acceleration is 100 m/s². what is the mass of the object?

You are a sales representative for a company that makes a new alternate fuel for vehicles. you have prepared a presentation for the environmental engineers to sell your new product. what question do you expect the audience to ask regarding whether the new fuel will cause less damage to the environment? a. do we have to change any parts of the vehicle to use this alternate fuel? b. will the vehicles get better fuel mileage with the alternate fuel? c. how much greenhouse gas does your fuel produce compared with current fuel sources? d. is the alternate fuel more expensive than fossil fuel?