An eagle flies from its perch in a tree to the ground to capture and eat its prey. describe its energy transfromation

A container is ﬁlled with water to a depth of 26.2 cm. On top of the water ﬂoats a 16.1 cm thick layer of oil with a density of

Solnce55 [7]

Answer:

1.34 x 10^3 Pa

Explanation:

density of oil = 0.85 x 10^3 kg/m^3

g = 9.81 m/s^2

height of oil column = 16.1 cm = 0.161 m

Pressure on the surface of water = height of oil column x density of oil x g

= 0.161 x 0.85 x 10^3 x 9.81 = 1.34 x 10^3 Pa

Thus, the pressure on the surface of water is 1.34 x 10^3 Pa.

4 0

3 years ago

. Calculate the efficiency of a bicycle if the input work to turn the pedal is 45J and the output work is 20J. * 1 point 2.25 2.

cestrela7 [59]

20/45=0.4*100= 44.4 so the answer is..................................................

Answer: 44.4%

8 0

3 years ago

Which scenario presents a possible environmental impact due hydrogen fuel cells?

Mekhanik [1.2K]

The scenario that presents a possible environmental impact due to hydrogen fuel cells is that, the electricity used to supply the fuel cells with Hydrogen is produced using fossil fuels.

The question is incomplete, but these should have been the options;

a.) The fuel cells are used to power internal combustion engines rather than electric motors.

b.) The electricity used to supply the fuel cells with hydrogen is produced using fossil fuels.

c.) The combined exhaust emissions from fleets of buses equipped with fuel cells generates smog.

d.) None of these are correct.

The answer therefore is option B. The Hydrogen fuel cell is a device that uses Hydrogen as an energy source to power machines and to generate heat and electricity. It is a green energy alternative to fossil fuels as unlike fossil fuels, it doesn't produce green house gases and is non-toxic. Also, unlike other clean sources of energy like wind and water, it doesn't require a large area of land to be produced.

Hydrogen fuel cells work by combining hydrogen and oxygen atoms. The resulting energy produced is converted to electrical energy which can be used to power electrical motors, while the by-product, water is non-toxic, renewable and doesn't create smog.

However, to produce the hydrogen used in the cells, high amount of energy is required in order to separate hydrogen from oxygen. To accomplish this, fossil fuels such as coal, natural gas and oil are used, releasing harmful emissions which creates a negative environmental impact. This makes the answer to the above question option B. A better alternative though, is to use other renewable energy sources like wind or solar.

To learn more about the benefits of Hydrogen fuel cells, visit;

brainly.com/question/6501095

#SPJ4

8 0

2 years ago

Air at 400 kPa, 980 K enters a turbine operating at steady state and exits at 100 kPa, 670 K. Heat transfer from the turbine occ

Angelina_Jolie [31]

Answer:

a). $\frac{\dot{W}}{m}= 311$ kJ/kg

b). $\frac{\dot{\sigma _{gen}}}{m}=0.9113$ kJ/kg-K

Explanation:

a). The energy rate balance equation in the control volume is given by

$\dot{Q} - \dot{W}+m(h_{1}-h_{2})=0$

$\frac{\dot{Q}}{m} = \frac{\dot{W}}{m}+m(h_{1}-h_{2})$

$\frac{\dot{W}}{m}= \frac{\dot{Q}}{m}+c_{p}(T_{1}-T_{2})$

$\frac{\dot{W}}{m}= -30+1.1(980-670)$

$\frac{\dot{W}}{m}= 311$ kJ/kg

b). Entropy produced from the entropy balance equation in a control volume is given by

$\frac{\dot{Q}}{T_{boundary}}+\dot{m}(s_{1}-s_{2})+\dot{\sigma _{gen}}=0$

$\frac{\dot{\sigma _{gen}}}{m}=\frac{-\frac{\dot{Q}}{m}}{T_{boundary}}+(s_{2}-s_{1})$

$\frac{\dot{\sigma _{gen}}}{m}=\frac{-\frac{\dot{Q}}{m}}{T_{boundary}}+c_{p}ln\frac{T_{2}}{T_{1}}-R.ln\frac{p_{2}}{p_{1}}$

$\frac{\dot{\sigma _{gen}}}{m}=\frac{-30}{315}+1.1ln\frac{670}{980}-0.287.ln\frac{100}{400}$

$\frac{\dot{\sigma _{gen}}}{m}=0.0952+0.4183+0.3978$

$\frac{\dot{\sigma _{gen}}}{m}=0.9113$ kJ/kg-K

5 0

3 years ago

Calculate the wavelengths of the first five emission lines of the Balmer series for hydrogen

In-s [12.5K]

Answer:

Explanation:

The Balmer series in a hydrogen atom relates the possible electron transitions down to the n = 2 position to the wavelength of the emission that scientists observe. In quantum physics, when electrons transition between different energy levels around the atom (described by the principal quantum number, n) they either release or absorb a photon. The Balmer series describes the transitions from higher energy levels to the second energy level and the wavelengths of the emitted photons. You can calculate this using the Rydberg formula.

5 0

3 years ago