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3 years ago

Which causes a rainbow in the sky?

1 answer:

7 0

Sunlight (white light) refracts through droplets of water in the atmosphere and this causes a rainbow in the sky. The correct option among all the options that are given in the question is the third option or option "C". The rainbow is caused by the reflection, refraction and dispersion of sunlight in water droplets that are present in the atmosphere.

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A simple pendulum is made from a 0.54-m-long string and a small ball attached to its free end. The ball is pulled to one side th

Serga [27]

Answer:

0.37sec

Explanation:

Period of oscillation of a simple pendulum of length L is:

T = 2 π × √ (L /g)

L=length of string 0.54m

g=acceleration due to gravity

T-period

T = 2 x 3.14 x √[0.54/9.8]

T = 1.47sec

An oscillating pendulum, or anything else in nature that involves "simple harmonic" (sinusoidal) motion, spends 1/4 of its period going from zero speed to maximum speed, and another 1/4 going from maximum speed to zero speed again, etc. After four quarter-periods it is back where it started.

The ball will first have V(max) at T/4,

=>V(max) = 1.47/4 = 0.37 sec

3 0

3 years ago

A 51.0-kg woman wearing high-heeled shoes is invited into a home in which the kitchen has vinyl floor covering. The heel on each

chubhunter [2.5K]

Answer:

Pressure = 9.94 x 10⁶ Pascals

Explanation:

given data

mass = 51 kg

radius = 0.400 cm

solution

we know Pressure that is express as here

Pressure = total force on an area ÷ the area of the area .................1

and

Force is the woman's weight so weight will be

Weight = mass × gravity .................2

put here value

Weight = 51 × 9.8 m/s²

Weight = 499.8 Newtons

and

Area of a circle of bottom of the heel = (π) × (radius)² ...................3

put here value

Area = (π) × (0.40 cm)²

Area = 0.502654 cm²

Area = 0.0000502654 m²

and

now we put value in equation 1 we get

Pressure = force ÷ area

Pressure = 499.8 ÷ 0.0000502654

Pressure = 9943221.381 N/m²

Pressure = 9.94 x 10⁶ Pascals

6 0

3 years ago

A 2.1 ✕ 103-kg car starts from rest at the top of a 5.9-m-long driveway that is inclined at 19° with the horizontal. If an avera

Lina20 [59]

Answer:

3.9 m/s

Explanation:

We are given that

Mass of car,m= $2.1\times 10^3 kg$

Initial velocity,u=0

Distance,s=5.9 m

$\theta=19^{\circ}$

Average friction force,f= $4.0\times 10^3 N$

We have to find the speed of the car at the bottom of the driveway.

Net force, $F_{net}=mgsin\theta-f=2.1\times 10^3\times 9.8sin19-4.0\times 10^3$

Where $g=9.8 m/s^2$

Acceleration, $a=\frac{F_{net}}{m}=\frac{2.1\times 10^3\times 9.8sin19-4.0\times 10^3}{2.1\times 10^3}$

$v=\sqrt{2as}$

$v=\sqrt{2\times \frac{2.1\times 10^3\times 9.8sin19-4.0\times 10^3}{2.1\times 10^3}\times 5.9}$

v=3.9 m/s

7 0

3 years ago

In an RLC series circuit that includes a source of alternating current operating at fixed frequency and voltage, the resistance

maw [93]

Answer:

Capacitive Reactance is 4 times of resistance

Solution:

As per the question:

R = $X_{L} = j\omega L = 2\pi fL$

where

R = resistance

$X_{L} = Inductive Reactance$

f = fixed frequency

Now,

For a parallel plate capacitor, capacitance, C:

$C = \frac{\epsilon_{o}A}{x}$

where

x = separation between the parallel plates

Thus

C ∝ $\frac{1}{x}$

Now, if the distance reduces to one-third:

Capacitance becomes 3 times of the initial capacitace, i.e., x' = 3x, then C' = 3C and hence Current, I becomes 3I.

Also,

$Z = \sqrt{R^{2} + (X_{L} - X_{C})^{2}}$

Also,

Z ∝ I

Therefore,

$\frac{Z}{I} = \frac{Z'}{I'}$

$\frac{\sqrt{R^{2} + (R - X_{C})^{2}}}{3I} = \frac{\sqrt{R^{2} + (R - \frac{X_{C}}{3})^{2}}}{I}$

${R^{2} + (R - X_{C})^{2}} = 9({R^{2} + (R - \frac{X_{C}}{3})^{2}})$

${R^{2} + R^{2} + X_{C}^{2} - 2RX_{C} = 9({R^{2} + R^{2} + \frac{X_{C}^{2}}{9} - 2RX_{C})$

Solving the above eqn:

$X_{C} = 4R$

6 0

3 years ago

What is the reaction for P₄ + 5 O₂ --> 2 P₂O₅

mixas84 [53]

Answer:

Combination or synthesis

Explanation:

The reaction is a combination or synthesis reaction in which two or more substances combines to give a single product.

In such a reaction there is formation of compounds from the union of their constituent elements.

The driving force for such reactions is the large and negative heat of formation of the product.

So, this is a combination reaction.

7 0

2 years ago