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3 years ago

The Sears Tower in Chicago is approximately 444 m tall Suppose a book

Physics

1 answer:

Reptile [31]3 years ago

4 0

Answer:

A. 66.0 m/s downwards

Explanation:

The Tower has a height of 444m

The book is dropped ,finding the velocity of the book 222m above the ground, means the book will be on air for a height of 222 m .

Apply the formula for free fall in a horizontal projection as;

h= u²×sin²∅ /2g where

h= maximum height =222m

g= acceleration due to gravity =9.81 m/s²

∅ = projectile angle = 0

u = velocity of the book

Applying the formula as ;

h= u²×sin²∅ /2g

222 = u²/2*9.81

222*19.62 = u²

4355.64 = u²

√4355.64 = u

65.99 m/s = u

66 m/s downwards

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A 40-W lightbulb is 1.7 m from a screen. What is the intensity of light incident on the screen? Assume that a lightbulb emits ra

Sonja [21]

Answer:

Intensity, $I=1.101\ W/m^2$

Explanation:

Power of the light bulb, P = 40 W

Distance from screen, r = 1.7 m

Let I is the intensity of light incident on the screen. The power acting per unit area is called the intensity of the light. Its formula is given by :

$I=\dfrac{P}{A}$

$I=\dfrac{P}{4\pi r^2}$

$I=\dfrac{40\ W}{4\pi (1.7\ m)^2}$

$I=1.101\ W/m^2$

So, the intensity of light is $1.101\ W/m^2$ .

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4 years ago

In a series RLC resonance circuit, the resonance frequency f0 = 700 kHz. The resistor R = 10 Ohm. The specified bandwidth (BW) s

sladkih [1.3K]

Answer:

quality factor (Q) = 69.99

inductor = 1.591 x 10⁻⁴ H

capacitor = 3.248 x 10⁻¹⁰ F

Explanation:

Given;

resonance frequency (F₀) = 700 kHz

resistor, R = 10 Ohm

bandwidth (BW) = 10 kHz

bandwidth (BW) $= \frac{R}{2\pi L}$

$BW = \frac{R}{2\pi L}$

make L (inductor) the subject of the formula

$L = \frac{R}{2\pi *BW} = \frac{10}{2\pi *10,000} =1.591 *10^{-4} \ H = \ 0.1591\ mH$

$F_o =\frac{1}{2\pi\sqrt{LC} } \\\\\sqrt{LC} = \frac{1}{2\pi F_o} \\\\LC = \frac{1}{4\pi ^2F_o^2}= \frac{1}{4\pi ^2(700,000)^2} = 5.168*10^{-14}$

make C (capacitor) the subject of the formula

$C = \frac{5.168*10^{-14}}{1.591*10^{-4}} = 3.248*10^{-10} \ F = \ 3.248*10^{-4} \ \mu F$

quality factor (Q) $= \frac{1}{R} \sqrt{\frac{L}{C}} \ = \frac{1}{10} \sqrt{\frac{1.591*10^{-4}}{3.248*10^{-10}}}=69.99$

quality factor (Q) = 69.99

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4 years ago

How can humidity be used to predict if it is going to rain?

postnew [5]

1. Humidity cannot be used to predict rain.
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3. Tempurature doesn't affect humidity.

4. Not sure but I think its the 3rd one

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3 years ago

(Thought question) At noon On June 21 will the shadow length of 42 degrees north latitude be shorter or longer than it is on Mar

g100num [7]

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3 years ago

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Rudiy27

Answer:true

Explanation:

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3 years ago

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