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Akimi4 [234]
3 years ago
7

How can sand dunes be saved?

Physics
2 answers:
Anton [14]3 years ago
6 0
Vegetation can be planted or wooden sand fences can be in place for a healthy dune system
Margarita [4]3 years ago
5 0
Sand dunes refers to accumulation of sand grains, which is shaped into a mound by the wind. Sand dunes are first line of protection against coastal storm and beach erosion. Sand dunes destruction can be caused by many factors, but the most prominent factor is human activity. The sand dunes can be preserve and saved by planting beach grasses, erecting sand fencing, erecting and using public crossovers, keeping boats off from the sand dunes and desisting from the act of burning beach grasses.<span />
You might be interested in
An 88 kg worker stands on a bathroom scale in a motionless elevator. When the elevator begins to move, the scale reads 900 N. Fi
Aleks [24]

Answer:

The magnitude is "3.8 m/s²", in the upward direction.

Explanation:

The given values are:

Mass,

m = 88 kg

Scale reads,

T = 900 N

As we know,

⇒  N=mg

On substituting the given values, we get

⇒      =88\times 9.8

⇒      =862.4 \ N

Now,

⇒  T=mg-ma

On substituting the given values in the above equation, we get

⇒  900=862.4-9.8 a

On subtracting "862.4" from both sides, we get

⇒  900-862.4=862.4-9.8 a-862.4

⇒              37.6=-9.8a

⇒                   a=-\frac{37.6}{9.8}

⇒                   a=3.8 \ m/s^2 (upward direction)

8 0
3 years ago
Anyone knows this? Please answer... Spam will be reported.
Yakvenalex [24]

Answer:

The correct option is;

The assertion is correct, but reason wrong

Explanation:

The question is with regards to the relationship between work, energy, power, and velocity

The mass of each of the persons running up the staircase = Different

The time it takes each person to run up the stairs = Equal time

Let, 'm₁' and 'm₂' represent the mass of each of the persons that ran up the stairs and m₁ > m₂

Let 't' represent the equal time it takes then to run up the stairs

Let 'h' represent the height of the stairs

The energy, 'E', it takes to run up the stairs is equal to the potential energy, P.E., obtained at the top of the stairs

P.E. = m·g·h

Where;

m = The mass of the person at an elevated height

g = The acceleration due to gravity = Constant

h = The height reached above ground level

Given that the height reached is the same for both of the persons, we have

For m₁, P.E.₁ = m₁·g·h and for m₂, P.E.₂ = m₂·g·h

Therefore, where, m₁ > m₂, we have;

P.E.₁ > P.E.₂

∴ E₁ > E₂

Power, 'P', is the rate at which energy is expended

∴ Power, P = E/t

∴ P₁ = E₁/t  > P₂ = E₂/t

Therefore, the person with the greater mass, 'm₁', uses more power than the person of mass 'm₂', in running up the stairs

Therefore, the assertion is correct

The average velocity, vₐ = (Total distance traveled, d)/(Total time taken, t)

Given that the distance, 'd', covered in running up the stairs by both persons is the same, and the time it takes them to complete the distance, 't', is also the same, we have;

The average velocity of the person with the greater mass m₁ is the same as the average velocity of the person with mass, m₂

Therefore, the reason is wrong

The answer is that the assertion is correct, but reason wrong

6 0
2 years ago
Which of these is the most ductile? A. clay B. gold C. wood D. glass
Feliz [49]
I'm pretty sure the answer is gold
8 0
3 years ago
1. You have a cat who has a mass of 10 kg and is
disa [49]

Answer:

1) F = 100N

2) a = 2 m/s²

3) m = 25 kg

Explanation:

1) F = ma ( F = ?, m = 10 kg, a = 10 m/s² )

  F = 10×10

  F = 100 N

2) F = ma ( F = 20N, m = 10 kg, a = ? )

   20 = 10×a

   10a = 20

   a = 20/10

   a = 2 m/s²

3)F = ma ( F = 100N, m = ?, a = 4 m/s² )

  100 = m×4

  4m = 100

  m = 100/4

  m = 25 kg

Hope that helps! Good luck!

 

7 0
3 years ago
A blue-green photon (λ = 488 nm ) is absorbed by a free hydrogen atom, initially at rest. What is the recoil speed of the hydrog
Natalka [10]

Answer:

The recoil speed is 2.207\times 10^{4} m/s

Solution:

Wavelength of a blue-green photon, \lambda_{BG} = 488 nm = 488\times 10^{- 9} m

Now, the energy associated with the blue-green photon:

E_{BG} = \frac{hc}{\lambda_{BG}}

where

h = Planck's constant

C = speed of light ion vacuum

E_{BG} = \frac{6.626\times 10^{- 34}\times 3\times 10^{8}}{488\times 10^{- 9}}

E_{BG} = 4.07\times 10^{- 19} J

Also, we know that the recoil speed can be calculated by the KInetic energy which is equal to the Energy of the blue-green photon:

KE_{H} =\frac{1}{2}m_{p}v_{H}

where

v_{H} = velocity of Hydrogen atom

m_{p} = 1.67\times 10^{- 27} kg = mass of H-atom

Now,

KE_{H} =\frac{1}{2}m_{p}(v_{H})^{2}

4.07\times 10^{- 19} =\frac{1}{2}\times 1.67\times 10^{- 27}\times (v_{H})^{2}

v_{H} = \sqrt(4.87\times 10^{8}) = 2.207\times 10^{4} m/s

7 0
3 years ago
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