The correct answer is 1 and 4.
Burning of fossil fuels releases harmful gases to the atmosphere which leads to climate change. Burning of hydrogen gas releases water which has no negative effect on climate.
Burning of both fossil fuels and hydrogen takes place inside expensive fuel cells.
Fossil fuels are widely available and easy to locate whereas hydrogen is available in the combined form with other elements. Hydrogen are not found in pure form on earth.
Fossil fuels are non-renewable source of energy which means they cannot be replaced in short time.
Answer:
19.5°
Explanation:
The energy of the mass must be conserved. The energy is given by:
1) 
where m is the mass, v is the velocity and h is the hight of the mass.
Let the height at the lowest point of the be h=0, the energy of the mass will be:
2) 
The energy when the mass comes to a stop will be:
3) 
Setting equations 2 and 3 equal and solving for height h will give:
4) 
The angle ∅ of the string with the vertical with the mass at the highest point will be given by:
5) 
where l is the lenght of the string.
Combining equations 4 and 5 and solving for ∅:
6) 
Answer:
4000 Hz
Explanation:
An anti-alias filter is usually added in front of the ADC to limit a certain range of input frequencies in order to avoid aliasing. This filter is usually a low pass filter that passes low frequencies but attenuates the high frequencies.
The Nyquist sampling criteria states that the sampling rate should be at least twice the maximum frequency component of the desired signal.
Sampling rate = 2(max input frequency)
From the relation we can find out the cut-off frequency for the anti-aliasing filter.
max input frequency = sampling rate/2
max input frequency = 8100/2 = 4050 Hz
Therefore, 4000 Hz would be an appropriate cut-off frequency for the anti-aliasing filter.
Well, essentially there would be changes to the organisms above the food chain, depending on the extent or how much the organisms require phytoplankton as a source of product to consume, they would slightly do down in number a lot or little.
