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3 years ago

What is light pollution?

1 answer:

8 0

Light pollution is excessive and inappropriate artificial light. The four components of light pollution are often combined and may overlap: Urban Sky Glow—the brightening of the night sky over inhabited areas. LightTrespass—light falling where it is not intended, wanted, or needed.

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A banked circular highway curve is designed for traffic moving at 58 km/h. The radius of the curve is 201 m. Traffic is moving a

skelet666 [1.2K]

Answer:0.077

Explanation:

Given

banked designed for traffic moving at $58 km/h\approx 16.11 m/s$

Radius of the curve 201 m

Actual traffic velocity = $37 km/h approx 10.27 m/s$

For banking of road

$tan\theta =\frac{v^2}{rg}$

$tan\theta =\frac{16.11^2}{201\times 9.81}$

$\theta =7.49^{\circ}$

Centripetal acceleration is given by

$a=\frac{v^2}{r}$

Taking component of centripetal acceleration

along and perpendicular to surface

$a_{parallel}=\frac{v^2cos\theta }{r}$

$a_{perpendicular}=\frac{v^2sin\theta }{r}$

From FBD

$mgsin\theta -f_s=ma_{parallel}$

$f_s=mgsin\theta -ma_{parallel}$ ----1

where $f_s$ is frictional force

$N-mgcos\theta =ma_{perpedicular}$

$N=mgcos\theta +ma_{perpedicular}$ ----2

and we know coefficient of friction is given by

$\mu =\frac{f_s}{N}$

$\mu =\frac{mgsin\theta -ma_{parallel}}{mgcos\theta +ma_{perpedicular}}$

$\mu =\frac{gsin\theta -\frac{v^2cos\theta }{r}}{gcos\theta +\frac{v^2sin\theta }{r}}$

$\mu =\frac{1.2804-0.5202}{9.726+0.068}$

$\mu =0.077$

7 0

3 years ago

Which statements correctly characterize a lunar eclipse? Select all that apply.

Zepler [3.9K]

A) it occurs when earth is between the sun and the moon

6 0

4 years ago

Charges that are different each other

adell [148]

Answer:

Like charges repel each other; unlike charges attract. Thus, two negative charges repel one another, while a positive charge attracts a negative charge. The attraction or repulsion acts along the line between the two charges. The size of the force varies inversely as the square of the distance between the two charges.

4 0

3 years ago

Read 2 more answers

The speedometer of your automobile shows that you are proceedig at a steady speed of 80 although your automobile is in accelerat

nika2105 [10]

Answer:

The engine must provide power to compensate friction

Explanation:

Accelerated Motion

Newton's first law states that a body will keep its speed or state of rest while no external net force is applied. Our automobile is running through a road which surface exerts a frictional force on the wheels. If we didn't use fuel, the automobile will eventually stop, because the unbalanced friction force causes deceleration. To compensate that force, we must provide power to the engine. When our speedometer shows a constant speed, the net force is zero, but the car needs to accelerate some, just to compensate the friction force.

The total acceleration keeps being zero, but the engine is actually doing work against friction.

7 0

3 years ago

A man of mass 70 kg climbs stairs of vertical height 2.5m. Calculate the work done against the force of gravity. (Take g = 9.81

Alona [7]

Answer:

1716.75 J

Explanation:

Step 1: First check what we are provided with. As per given question we have:

mass (m) = 70 kg, height (h) = 2.5 m and acceleration due to gravity (g) = 9.81 m/s².

Step 2: Check what we are asked to find out.

Work done = Change in Potential energy

The stuff required to solve this question is potential energy. Using the formula: P = mgh. Where P is Potential energy, m is mass, g is acceleration due to gravity and h is height.

Step 3: Substitute the known values in the above formula.

→ P = 70 × 2.5 × 9.81

→ P = 1716.75 J

Hence, the work done against the force of gravity is 1716.75 J.

3 0

2 years ago