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2 years ago

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1. A pulley system has efficiency 60%. Calculate mechanical advantage to make its velocity ratio 6 .How much amount of effort is

required to lift 3000 N load by using this pulley system?

1 answer:

lesya [120]2 years ago

8 0

Efficiency = Mechanical advantage / Velocity Ratio:

0.60 = M.A./6

MA = 0.6 * 6 = 3.6

The mechanical advantage is 3.6

Mechanical advantage = Force out / Force in

3.6 = 3000/ Force in

Force in = 3000/3.6

Force in = 833.33 N

Answer: 833.33N

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As the people sing in church, the sound level everywhere inside is 101 dB . No sound is transmitted through the massive walls, b

katovenus [111]

The sound level from 1 km away is 46.4 dB and the sound energy radiated through the windows and doors in 20 min is 332.6 J

<h3>What do you mean by sound radiates?</h3>

Multiple plate modes participate in the forced vibration of a baffled plate that produces sound. The emitted sound power depends on the activation of each plate mode by the external pressures as well as the radiation characteristics of the individual plate modes and their mutual interaction via their radiated sound, as shown in eq (20) and (24). The net contribution of the mutual interaction between plate modes to the overall sound power may be disregarded if a plate is activated in a manner that results in a plate vibration field that can be defined as reverberant with an equal distribution of energy over all modes.

(Lw) = 10·log (W/Wo) dB

Given:

sound level, $\beta= 101 dB$

Area, A = $22\;m^{2}$

Time, $\triangle t = 20\;min=1200\;s$

Intensity, $I=1\times 10^{-12}\;W/m^{2}$

$r=1\;km=1000\;m$

(a)

We know that, Sound level is,

$\beta=10\times log(\frac{I}{I_{o} } )$

Solving the above equation for sound intensity,

$I=I_{o} \times 10^{\frac{\beta}{10} }$

$I=1 \times 10^{-12} \times 10^{\frac{101}{10} }$

$I=0.0126\;W/m^{2}$

Therefore, The sound energy is,

$E=P\times \triangle t$

Substitute $P=I \times A$ in the above equation,

$E=I \times A \times \triangle t$

$E=0.0126 \times 22 \times 1200$

$E=332.6\;J$

(b)

Half of a sphere area with 1 km radius is equal to Area of the sound at 1 km distance,

$A_{hemisphere} = \frac{1}{2} \times 4 r^{2} \pi$

Substitute the known value in the above equation ,

$A_{hemisphere} = \frac{1}{2} \times 4 (1000)^{2} \pi$

$A_{hemisphere} = 6283185\;m^{2}$

Sound Intensity is,

$I = \frac{P}{A_{hemisphere}}$

Substitute $P=I \times A$ in the above equation,

$I = \frac{I \times A}{A_{hemisphere}}$

Substitute the known value in the above equation,

$I = \frac{0.0126 \times 22}{6283185}$

$I = 4.4 \times 10^{-8}\;W/m^{2}$

Sound level is,

$\beta=10\times log(\frac{I}{I_{o} } )$

Substitute the known value in the above equation,

$\beta=10\times log(\frac{4.4 \times 10^{-8} }{1 \times 10^{-12} } )$

$\beta=46.4\;dB$

To learn more about sound radiates, Visit:

brainly.com/question/20360072

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8 0

1 year ago

Identify how any organisms from the video showed variation, competition or overproduction. (Make sure to incude the name of the

Masja [62]

Answer:

Overproduction can lead to other side effects, which can be considered an advantage or a disadvantage. When more offspring are produced, it increases the odds of a spontaneous variation.

8 0

2 years ago

For a freely falling object dropped from rest, what is the acceleration at the

Zinaida [17]

The acceleration of the object after 3 seconds of fall is -9.8 m/s².

The given parameters;

initial velocity of the object, u = 0
time of motion of the object, t = 3 seconds

Acceleration is the change in velocity per change in time of motion.

The acceleration of the object after 3 seconds of fall is calculated as follows;

Since the object is in free fall, the object experiences only acceleration due to gravity.
the magnitude of this acceleration due to gravity is 9.8 m/s²
the direction of this acceleration is downwards

Thus, the acceleration of the object after 3 seconds of fall is -9.8 m/s².

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3 years ago

Consider a semi-spherical bowl machined out of wood (A drawing of a semi-spherical bowl can be found in UNIT- 4 Introduction, so

Mrrafil [7]

Answer:

The total surface are of the bowl is given by: 0.0532*pi m² (approximately 0.166533 m²)

Explanation:

The total surface area of the semi-spherical bowl can be decomposed in three different sections: 1) an outer semi-sphere of radius 12 cm, 2) an inner semi-sphere of radius 10 cm, and 3) the edge, which is a 2-dimensional ring with internal radius of 10 cm and external radius of 12 cm. We will compute the areas independently and then sum them all.

a) Outer semi-sphere:

A1 = 2*pi*r² = 2*pi*(12 cm)² = 288*pi cm² = 904.78 cm²

b) Inner semi-sphere:

A2 = 2*pi*(10 cm)² = 200*pi cm² = 628.32 cm²

c) Edge (Ring):

A3 = pi*(r1² - r2²) = pi*((12 cm)²-(10 cm)²) = pi*(144-100) cm² = 44*pi cm² = 138.23 cm²

Therefore, the total surface area of the bowl is given by:

A = A1 + A2 + A3 = 288*pi cm² + 200*pi cm² + 44*pi cm² = 532*pi cm² (approximately 1665.33 cm²)

Changing units to m², as required in the problem, we get:

A = 532*pi cm² * (1 m² / 10, 000 cm²) = 0.0532*pi m² (approximately 0.166533 m²)

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3 years ago

Which statement is true?

iogann1982 [59]

B
Think of inertia of getting into a car accident without a seat belt although the car stops you will not you would likely fly out the window

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2 years ago

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