A helicopter hovers 568 m above a field and 96 kJ of gravitational potential

Consider a river flowing toward a lake at an average velocity of 3 m/s at a rate of 500m3/sat a location 90 m above the lake sur

olga_2 [115]

Answer:

mechanical energy per unit mass is 887.4 J/kg

power generated is 443.7 MW

Explanation:

given data

average velocity = 3 m/s

rate = 500 m³/s

height h = 90 m

to find out

total mechanical energy and power generation potential

solution

we know that mechanical energy is sum of potential energy and kinetic energy

so

E = $\frac{1}{2}$ ×m×v² + m×g×h .............1

and energy per mass unit is

E/m = $\frac{1}{2}$ ×v² + g×h

put here value

E/m = $\frac{1}{2}$ ×3² + 9.81×90

E/m = 887.4 J/kg

so mechanical energy per unit mass is 887.4 J/kg

and

power generated is express as

power generated = energy per unit mass ×rate×density

power generated = 887.4× 500× 1000

power generated = 443700000

so power generated is 443.7 MW

3 0

3 years ago

A

asambeis [7]

Answer:

22Volts

Explanation:

The pd at the terminal is known as the emf

Since there are Ten 2.2V cells

Terminal voltage = number of cells * pd of one cell

Terminal voltage = 10 * 2.2

Terminal voltage = 22V

Hence the pd at the battery terminals is 22Volts

4 0

3 years ago

A skier is pulled by a towrope up a frictionless ski slope that makes an angle of 12 degrees with the horizontal. The rope moves

MArishka [77]

Answer:

Explanation:

Given,

Work done by the rope 900 m/s.
Angle of inclination of the slope = $\theta\ =\ 12^o$
Initial speed of the skier = v = 1.0 m/s
Length of the inclined surface = d = 8.0 m

part (a)

The rope is doing the work against the gravity on the skier to uplift up to the inclined surface. Therefore the work done by the rope is equal to the work done on the skier due to the gravity

$\therefore W_r\ =\ W_g\ =\ 900\ J$

In both cases the height attained by the skier is equal. and the work done by gravity does not depend upon the speed of the skier.

part (b)

Initial speed of the skier = v = 1.0 m/s.

Rate of the work done by the rope is power of the rope.

$Power\ =\ \dfrac{\Delta W}{\Delta t}\\\Rightarrow P\ =\ \dfrac{\Delta W}{\dfrac{d}{v}}\\\Rightarrow P\ =\ \dfrac{\Delta W\times v}{d}\\\Rightarrow P\ =\ \dfrac{900\times 1.0}{8.0}\\\Rightarrow P\ =\ 112.5\ Watt$

Part (c)

Initial speed of the skier = v = 2.0 m/s.

Rate of the work done by the rope is power of the rope.

$Power\ =\ \dfrac{\Delta W}{\Delta t}\\\Rightarrow P\ =\ \dfrac{\Delta W}{\dfrac{d}{v}}\\\Rightarrow P\ =\ \dfrac{\Delta W\times v}{d}\\\Rightarrow P\ =\ \dfrac{900\times 2.0}{8.0}\\\Rightarrow P\ =\ 225\ Watt$

4 0

3 years ago

The charge on any negatively charged oil droplet is always a whole-number multiple of the fundamental charge of a single electro

shusha [124]

Answer:

$1.6\times 10^{-18} C$

Explanation:

The fundamental charge of a single electron is $1.6\times 10^{-19} C$ .

If there are 10 excess electrons, the net charge that would be measured should be 10 times the fundamental charge of a single electron:

$Q=nq_e\\Q= 10\times 1.6\times 10^{-19} C\\Q= 1.6 \times 10^{-18} C$

3 0

3 years ago

Light incident upon a pane of glass slows down in passing through the glass, Does it emerge at a slower speed or at its initial

Simora [160]

Answer:

It will emerge at its initial speed not a slower speed.

Explanation:

It will emerge at the initial speed because the medium at the point of emergence is the same as the medium before incidence.

Light moves at a constant speed in any particular medium. Hence, the speed of light in air is constant in air and the speed of light in glass is constant in glass.

4 0

3 years ago