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3 years ago

What is the most effective way to protect dry lands from desertification

Physics

2 answers:

liberstina [14]3 years ago

5 0

Answer:

The correct answer is Planting a tree belt (C)

Explanation:

I just got it right on my test:)

Sonja [21]3 years ago

4 0

Answer: Planting a tree belt.

Explanation:

The most effective method by which the desertification of the soil can be controlled is by planting more and more trees.

The process of desertification occurs when there is a loss of vegetation, water bodies and animals from a particular area. Loss of trees makes the area look like desert.

So, planting trees along with some irrigation will help to cope with problem.

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A charge q = 3 × 10-6 C of mass m = 2 × 10-6 kg, and speed v = 5 × 106 m/s enters a uniform magnetic field. The mass experiences

NeX [460]

Answer:

Magnetic field, B = 0.004 mT

Explanation:

It is given that,

Charge, $q=3\times 10^{-6}\ C$

Mass of charge particle, $m=2\times 10^{-6}\ C$

Speed, $v=5\times 10^{6}\ m/s$

Acceleration, $a=3\times 10^{4}\ m/s^2$

We need to find the minimum magnetic field that would produce such an acceleration. So,

$ma=qvB\ sin\theta$

For minimum magnetic field,

$ma=qvB$

$B=\dfrac{ma}{qv}$

$B=\dfrac{2\times 10^{-6}\ C\times 3\times 10^{4}\ m/s^2}{3\times 10^{-6}\ C\times 5\times 10^{6}\ m/s}$

B = 0.004 T

B = 4 mT

So, the magnetic field produce such an acceleration at 4 mT. Hence, this is the required solution.

4 0

3 years ago

high frequency sound waves have a shorter wavelength and a higher A. amplitude B. pitch C. wavelength? than low frequency sound

gizmo_the_mogwai [7]

Pitch of the sound increases as frequency increases.
choose B pitch

8 0

3 years ago

Read 2 more answers

A bat emits a sound at a frequency of 30.0 kHz as it approaches a wall. The bat detects beats such that the frequency of the ech

Alex

Answer:

The speed of the bat is 5.02 m/s.

Explanation:

Given that,

Frequency = 30.0 kHz

Frequency of echo = 900 Hz

We need to calculate the frequency

Using formula of beat frequency

$f_{b}=f_{1}-f_{2}$

Put the value into the formula

$900=f_{1}-30\times10^{3}$

$f_{1}=900+30000$

$f_{1}=30900\ Hz$

We need to calculate the speed of the bat

Using Doppler equation

$f_{apr}=f\times(\dfrac{v_{sound}+v_{observer}}{v_{s}-v_{source}})$

Put the value into the formula

$30900=30000\times(\dfrac{340+v_{bat}}{340-v_{bat}})$

$\dfrac{30900}{30000}=\dfrac{340+v_{bat}}{340-v_{bat}}$

$1.03=\dfrac{340+v_{bat}}{340-v_{bat}}$

$340\times1.03-340=v_{b}+1.03v_{b}$

$10.2=2.03v_{bat}$

$v_{bat}=\dfrac{10.2}{2.03}$

$v_{bat}=5.02\ m/s$

Hence, The speed of the bat is 5.02 m/s.

6 0

3 years ago

A pendulum of mass 5.0 ???????? hangs in equilibrium. A frustrated student walks up to it and kicks the bob with a horizontal fo

Rudiy27

Answer:

a. 37.75°

b. 6.21 m

Explanation:

a. The horizontal force acting on a pendulum bob is given as:

F = mgsinθ

where m = mass of bob

g = acceleration due to gravity

θ = angle string makes with the vertical or angle of displacement

Making θ subject of formula, we have:

θ = $sin^{-1}(\frac{F}{mg} )$

θ = $sin^{-1} (\frac{30}{5*9.8})$

θ = 37.75°

The maximum angle of displacement is 37.75°

b. Period of a pendulum is given as:

$T = 2\pi\sqrt{ \frac{L}{g} }$

where L = length of string

Therefore, making L subject of formula:

$L = \frac{gT^2}{4\pi^2}$

$L = \frac{9.8 * 5^2}{4\pi^2} \\\\\\L = 6.21 m$

The string holding the pendulum has to be 6.21 m long.

4 0

3 years ago

A 25 kg box on a horizontal frictionless surface is moving to the right at a speed of 5.0 m s. The box hits and remains attached

seropon [69]

Answer:

Explanation:

Work done by the spring is negative .

Work done by force F creating displacement d is given by the following expression .

Work = F x d

Both force and displacement are vector quantity .

When direction of force and direction of displacement is same , work is positive . When direction of force and direction of displacement is opposite , work is negative .

When spring is compressed , it exerts a restoring or opposing force in a direction opposite to the direction of displacement of box . Hence here force is opposite to displacement . Restoring force acts opposite to displacement . Hence work done by spring on box is negative .

6 0

3 years ago