Answer:
D. Test a piece of treated iron and a piece of untreated iron under the same conditions.
Explanation:
A controlled experiment is defined as an experiment where the experimenter or the researcher tries to test or experiment his result by changing one variable at a time and keeping the other factors under the same conditions and sees how it effects the result.
The factors which can be changed in an experiment is called its variables.
In the context, testing a piece of treated iron as well as a untreated piece of iron under the same working conditions forms a controlled experiment.
Answer:
434 Hz
Explanation:
According to the Doppler effect, when a source of a wave is moving towards an observer at rest, then the observer will observe an apparent frequency which is higher than the original frequency of the source.
In this situation, Tina is driving towards Rita. Tina is the source of the sound wave (the horn), while RIta is the observer. Since the original frequency of the sound is 400 Hz, Rita will hear a sound with a frequency higher than this value.
The only choice which is higher than 400 Hz is 434 Hz, so this is the frequency that Rita will hear.
Answer: B, increase the rate at which he turns the crank
Explanation: i got it right
Answer:
what is Jose potential energy
Explanation:
As we know that the maximum of thermal energy will be converted into mechanical energy.( The thermal energy will be given to us by engine.)
But the total thermal energy will not be converted into the mechanical energy, there will be some lost of energy. The lost of mechanical energy will be in multiple forms. 2 of them are
1.Heat : The mechanical energy heats up the engine and then it will lost some energy.
2.Noise : Some energy also lost in the sound or the noise comes out from the engine. It will consume some energy.
Also, the engine never be 100% efficient some amount of energy lost in environment also.
