¿Por qué los cambios de estado son cambios físicos y no químicos? Justifica. Necesito ayuda rápido xfavor:)

Suppose you use a machine that gives you a mechanical advantage of 2 to achieve an output force of 30newtons what must the input force be

Which is the best for showing percentages of different types of cars sold(gas hybrid , electric , other ) in the united states ?

Which are advantages of renewable resources? check all that apply. renewable energy supplies are completely reliable everywhere. some renewable resources will never be used up. little or no waste is produced by renewable resource plants. electricity can be generated in large quantities. many renewable energy facilities have lower operating costs.