Hmm...
dam power plant (not sure if this is considered renewable): benefits: as it creates a tourist spot bringing more money and provides electricity.
disadvantages: restricts flow of water to farms, costs millions to build.
solar power plant: benefits: sunlight just keeps coming, produces a lot of electricity for maybe half the cost.
disadvantages: takes a large crew to maintain, mostly needs to be in an open area.
Wind farm: benefits: wind we don't have to worry about much, just blows through and turns the turbines, and can produce electricity almost 24/7.
disadvantages: unsightly, needs open space and costs a lot to build
Take your pick!
Answer:
Flow Rate = 80 m^3 /hours (Rounded to the nearest whole number)
Explanation:
Given
- Hf = head loss
- f = friction factor
- L = Length of the pipe = 360 m
- V = Flow velocity, m/s
- D = Pipe diameter = 0.12 m
- g = Gravitational acceleration, m/s^2
- Re = Reynolds's Number
- rho = Density =998 kg/m^3
- μ = Viscosity = 0.001 kg/m-s
- Z = Elevation Difference = 60 m
Calculations
Moody friction loss in the pipe = Hf = (f*L*V^2)/(2*D*g)
The energy equation for this system will be,
Hp = Z + Hf
The other three equations to solve the above equations are:
Re = (rho*V*D)/ μ
Flow Rate, Q = V*(pi/4)*D^2
Power = 15000 W = rho*g*Q*Hp
1/f^0.5 = 2*log ((Re*f^0.5)/2.51)
We can iterate the 5 equations to find f and solve them to find the values of:
Re = 235000
f = 0.015
V = 1.97 m/s
And use them to find the flow rate,
Q = V*(pi/4)*D^2
Q = (1.97)*(pi/4)*(0.12)^2 = 0.022 m^3/s = 80 m^3 /hours
Answer:
Approximately 
.
Explanation:
<h3>Solve this question with a speed-time plot</h3>
The skateboarder started with an initial speed of 
and came to a stop when her speed became 
. How much time would that take if her acceleration is 
?
.
Refer to the speed-time graph in the diagram attached. This diagram shows the velocity-time plot of this skateboarder between the time she reached the incline and the time when she came to a stop. This plot, along with the vertical speed axis and the horizontal time axis, form a triangle. The area of this triangle should be equal to the distance that the skateboarder travelled while she was moving up this incline until she came to a stop. For this particular question, that area is approximately equal to:
.
In other words, the skateboarder travelled 
up the slope until she came to a stop.
<h3>Solve this question with an SUVAT equation</h3>
A more general equation for this kind of motion is:
,
where:
and 
are the initial and final velocity of the object,
is the constant acceleration that changed the velocity of this object from to , and
is the distance that this object travelled while its velocity changed from to .
For the skateboarder in this question:
.
Answer:
Explanation:
Sun's dynamo means the process that produce Sun's magnetic field.
The mechanism inside a Sun acts like a generator that produces electric current and magnetic field.
Magnetic field with in the Sun are extended out and around. Magnetic field of lines get twisted due to rotation of Sun.
The material that flows inside the Sun plays an important role in Sun's dynamo. At surface the flow rate is about 20 m/s but as it moves towards equator, it becomes way too slow taking about 11 years of time.
Due to the this magnetic field, several sun spots are formed on the surface.
The number of sunspots keep on changing from minimum to maximum number resulting into change in the magnetic pole. In each cycle polarity get reversed hence the overall magnetic cycle has an interval of 22 years.
