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How does the construction of dams positively affect natural resources?
by providing water for irrigation and restoring trees to areas where forests once existed
by creating reservoirs, preventing flooding, and renewing destroyed ecosystems
by preventing flooding, creating reservoirs, and providing water for irrigation
by renewing destroyed ecosystems and restoring trees to areas where forest once ersted

Answer:

5m/s²

Explanation:

Initial Velocity= 40m/s

Final Velocity=60m/s

Time = 4s

a=(v-u)/t

a=60-40/4

a=20/4

a=5m/s²

Answer:

The angle is 18.3 degree.

Explanation:

A uniformly charged infinite plane, density σ = 4 x 10^-9 C/cm^2, is placed vertically in air. A small ball of mass 8 g, with charge q = 10^-8 C, hangs close to the plane, so that the string is initially parallel to the plane. Take g = 9.8m/s2. When in equilibrium, by what angle is the string hanging the ball to the plane?

surface charge density, σ = 4 x 10^-5 C/m^2

Charge, q = 10^-8 C

mass, m = 0.008 kg

Let the angle is A and the tension in the string is T.

The electric field due to a plane is

[tex]E =\frac{\varepsilon \sigma }{2\varepsilon o}\\\\E =\frac{4\times 10^{-5}}{2\times 8.85\times 10^{-12}}\\\\E = 2.26\times 10^6 V/m \\[/tex]

Now equate the forces,

[tex]T sin A = q E.... (1)\\\\T cos A = m g ..... (2)\\\\divide (1) by (2)\\\\tan A = \frac{10^{-8}\times 2.6\times 10^6}{0.008\times 9.8}\\\\tan A = 0.33\\\\ A = 18.3 degree[/tex]

Answer:

Explanation:

The formula for centripetal acceleration is

[tex]a_c=\frac{v^2}{r}[/tex] . Filling in:

[tex]2.5=\frac{v^2}{15}[/tex] and

[tex]v=\sqrt{2.5(15)}[/tex] so

v = 6.1 m/s

Answer:6.26*10^-4

Explanation:

The magnetic flux through the loop is 6.255 x 10⁻⁴ Weber.

The number of magnetic field lines passing through a cross-section area defines the magnetic flux. It is denoted by ∅.

∅ = BAcosθ

Given is the magnetic field B = 0.152T, radius r = 0.04m and the angle of orientation θ=35.0 degrees

Area of cross- section A = πr² = 3.14 x ( 0.04)² = 5.024 x 10⁻³ m²

Magnetic flux, ∅ =  0.152 x  5.024 x 10⁻³ x cos 35°

∅ = 6.255 x 10⁻⁴ Weber

Thus, the magnetic flux through the loop is 6.255 x 10⁻⁴ Weber.

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Answer:

ME= 196.2 J

KE= 136.2

Explanation:

potential energy=mgh 2*9.81*10

Our ME is quivalent to PE as that is the toal amount of energy in the system

Kinetic energy= 1/2 m[tex]v^{2}[/tex]

to solve for kinetic enrgy we need to use a kinaetmtic equation that help us find velocity

vf= vi+at

but we need to find time first

d=vi+1/2(accelretaion)[tex]t^{2}[/tex]

7=0+1/2(9.81)[tex]t^{2}[/tex]

t= 1.19 s

vf= 0+ 9.81*1.19

vf= 11.67 m/s

Now

1/2 m[tex]v^{2}[/tex]

1/2*2*[tex]11.67^{2}[/tex]

= 136. 2

or we could just (PE/10)*7

so (196.2/10)*7

Answer:

Gravity

Explanation:

There's no gravity on space so you're floating

Answer: hi your question is incomplete  attached below is the complete question

answer :

magnitude of acceleration :  | a | = g = 9.81 m/s^2

direction : a = - g j

Explanation:

Neglecting Air resistance

magnitude of acceleration :

| a | = g = 9.81 m/s^2

Direction of acceleration

a = - g j  ( given that the direction of acceleration is against the acceleration due to gravity i.e. in the opposite direction )

Answer:

A. The size of the ice patches

Explanation:

In an experiment, the control variable also known as the CONSTANT is the variable that must be kept uniform or the same for all groups throughout the experiment in order not to influence the outcome of the experiment.

According to the experiment described in this question, the effect of different salts on melting points is investigated by a student. Sodium chloride (NaCl), Calcium Chloride (CaCl2), Potassium Carbonate (KCO3) and inert sand are the four types of salt used. The volume of the ice used and melted was finally measured. This means that the SIZE OF THE ICE PATCHES USED is the control variable of the experiment as the same size was used for all groups throughout.

Answer:

the size of the ice patches

Explanation:

Answer:

Hence, the height of the ceiling at the center is 44.72 feet.

Explanation:

Consider that a whispering gallery has a length of 120 feet, and the foci are located 40 feet from the center.

Assume that the shape is a horizontal semi-ellipse with a center (0,0) and has the equation,

[tex]\frac{x^{2} }{ a^{2} } + \frac{y^{2} }{b^{2} } =1[/tex]  where a>b,

so,

2a = 120

a = 60

and

c = 40

Therefore, the equation of the ellipse is,

[tex]c^{2} = a^{2} -b^{2} \\\\40^{2} = 60^{2} -b^{2}\\\\b^{2} =2000\\\\b= 44.72.[/tex]

Answer:

39 m/s²

Explanation:

initial Velocity (u) = 9m/s

acceleration (a) = 1.5m/s²

time(t) = 20s

V=u + at

V=9 + 1.5(20)

V=9 + 30

V=39m/s

Answer:

The definition of acceleration is a change in the rate of motion, speed or action.

Acceleration is the rate of change of velocity.

[tex]acceleration = \frac{(final \: velocity - initial \: velocity)}{time} \\ or \\ a = \frac{(v - u)}{t} \\ \\ The \: S.I. \: unit \: of \: acceleration \: is \: \frac{m}{ {s}^{2} } \: or \: m {s}^{ - 2} [/tex].

My last year's notes on acceleration is attached. Hope it helps you!!

Answer:

First Condition of Equilibrium

For an object to be in equilibrium, it must be experiencing no acceleration. This means that both the net force and the net torque on the object must be zero. Here we will discuss the first condition, that of zero net force. ... Fnet=0 F net = 0.

Scalar quantity are physical quantities that have just magnitude, not direction.

Answer:

2.89 hours

Explanation:

given :

Vo = 72 km/h

Vt = 90 km/h

S = 234 km

find : the time taken (t) = ?

solution :

2.a.s = Vt² - Vo²

2.a.(234) = 90²- 72²

468.a = 8100 - 5184

= 2916

a = 2916/468 = 6.23 km/h²

so,

t = (Vt-Vo) /a

= (90-72)/ 6.23

= 18/ 6.23

= 2.89 hours

Answer:

0.25s

Explanation:

5/20 = 0.25s

This might be correct

Answer:

1.2 N

Explanation:

Given that,

We are asked to calculate force exerted (F).

[tex]\longrightarrow[/tex] F = ma

[tex]\longrightarrow[/tex] F = (0.15 × 8) N

[tex]\longrightarrow[/tex] F = 1.2 N

The English Bill of Rights helped to shape the colonists' views of government by promoting the ideas of individual liberty, representative democracy, and limited government.

The English Bill of Rights is a document that was passed by the Parliament of England in 1689. It was a key moment in the development of modern democratic government, as it established certain rights and protections for English citizens, such as the right to bear arms, the right to a fair trial, and the prohibition of cruel and unusual punishment.

The English Bill of Rights also limited the power of the monarchy, requiring the king or queen to obtain the consent of Parliament before levying taxes or making other important decisions. Its influence can still be seen today in many democracies around the world.

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Answer:

The direction of friction force is toards north.

Explanation:

A tool box is at rest on the back of a track. The truck is accelerating towards north.

As the frame of reference is acceleratinf so it is a non inertial frame  of reference.

Thus, teh toolkit experineces a pseudo force towards the south direction.

According to the question, the toolbox is at rest so the fiction force is balances by teh psheudoforce, and thus teh friction force is acting toards north.

Answer:

[tex]N_B-W_B = 0[/tex]

Explanation:

There are two forces acting on object B. If we consider the law of equilibrium, then the two forces must be equal in magnitude, for the object to remain in equilibrium position:

[tex]N_B = W_B\\\\N_B-W_B = 0[/tex]

Therefore, the correct answer of the given question, from the given choices, is:

[tex]N_B-W_B = 0[/tex]

Answer:

0.2

Explanation:

The given parameters are;

The acceleration of the train, a = 0.2·g

The mass of the person standing on the train = m

Let μ represent the coefficient of static friction, we have;

The force acting on the person, F = m × a = m × 0.2·g

The force of friction acting between the feet and the floor, [tex]F_f[/tex] = m·g·μ

For the person not to slide we have;

The force acting on the person = The force of friction acting between the feet and the floor

F = [tex]F_f[/tex]

∴ m × 0.2·g = m·g·μ

From which we get;

0.2 = μ

The coefficient of static friction that must exist between the feet and the floor if the person is not to slide, μ = 0.2.

Answer:

Black and yellow strips.

Explanation:

Color of shirt is blue and white stripes

When the shirt is seen in the yellow light, the blue color do not reflect any color so it appears black and the white color reflects the yellow light so it appears yellow.

Thus, the color of shirt is blue appears black and white appears yellow.

Answer:

Explanation:

This is a First Law of thermodynamics problem. We have to remember that the total energy available to a system is constant throughout the whole problem and that energy cannot be created or destroyed. So we need to find the total energy available right at the start. Well it just so happens that we are told that the total energy is 1000J and that it is all potential energy when the sphere is at rest and is 25 m off the ground. If the object isn't moving, all the energy is potential until it starts moving and the energy begins to convert from potential to kinetic a little bit at a time. The thing that we don't know is the mass of the shpere. Begin with the fact that the PE = 1000 (I'm going to se 2 sig fig's since there's only 1 in 1000). If

PE = 1000 and PE = mgh, then

1000 = m(9.8)(25) so

m = 4.1 kg

We also need the height at which this sphere has a PE of 600. Again, if

PE = 600 and PE = mgh, then

600 = (4.1)(9.8)h so

h = 15 Filling in the total energy equation now, using the fact that the total energy available to the system is 1000J:

TE = PE + KE and

1000 = (4.1)(9.8)(15) + [tex]\frac{1}{2}(4.1)v^2[/tex] and we are looking for v.

1000 = 6.0 × 10² + 2.1v² so

[tex]v=\sqrt{\frac{1000-6.0*10^2}{2.1} }[/tex] and

[tex]v=\sqrt{\frac{4.0*10^2}{2.1} }[/tex] gives us

v = 14 m/s

Answer:

This happens because the tin is made of estañum, and the estañum is denser than the water.

Remember the relation:

density = mass/volume

The general rule is that if an object is denser than water, it will sink

If an object is less dense than water, like a piece of wood, it will float.

And if an object has the same (or nearly the same) density as water, it will float, but fully submerged.

Based on that, we can conclude that the tin will sink because it's density is larger than the density of the water.

Answer:

Explanation:

This is basically asking you what the definition of Normal force is. Normal force is the force that pushes back against the weight of something that is sitting (or standing or lying) perpendicular to it. That's why, when you stand on a floor you don't crash through the floor OR go shooting up into space. The Normal force is equal but opposite to your weight. The floor exerts the normal force (pushing up and is positive) while your weight is opposing it (pushing down and is negative.)  Perpendicular is the key word here, I believe.

A normal force acts perpendicular to an object. It is the force exerted by a surface to support the weight of an object resting on it.

The normal force acting against an object slowing it down or acting with an object adding to its speed, are not accurate descriptions of the normal force. The normal force primarily deals with the support of an object on a surface and is directed perpendicular to that surface.

Normal force is the force that pushes back against the weight of something that is sitting (or standing or lying) perpendicular to it. That's why, when you stand on a floor you don't crash through the floor OR go shooting up into space. The Normal force is equal but opposite to your weight. The floor exerts the normal force (pushing up and is positive) while your weight is opposing it (pushing down and is negative.)

Therefore, A normal force acts perpendicular to an object. It is the force exerted by a surface to support the weight of an object resting on it.

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Answer:

To find the height the following formula should be used:  

v 2 = u 2 + 2aH

Explanation:

Assuming this occurs on earth,  a= 9.8 ms -2

 -2        2

12=0+2 x9.8 x H

144

_______ =H

2 x 9.8

H= 7.35m

Answer:

The correct answer is options (1) and (4).

Explanation:

Due to the rotation of the earth Coriolis force is generated. As the earth rotates from the west to the east, it changes the pattern of global wind and ocean water movement.

This force allows the ocean surface water to move in the clockwise direction in the northern hemisphere, and anticlockwise in the southern hemisphere.

Thus, the correct answer is options (1) and (4).

Answer:

amplitude

Explanation:

sound travel and it amplifies

Answer:

[tex]v_y = 5\ m/s[/tex]

Explanation:

The vertical downward component of the speed of the bike can be simply found out by using the following geometric formula:

[tex]v_y = vSin\theta[/tex]

where,

[tex]v_y[/tex] = vertical downward component of speed = ?

v = speed = 10 m/s

θ = angle of slope = 30°

Therefore,

[tex]v_y = (10\ m/s)Sin\ 30^o\\v_y = 5\ m/s[/tex]