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Which is heavier 1kg of iron or 1 kg of feathers?

Tema [17]

-- On Earth, 1 kg of anything weighs 9.81 Newtons (2.205 pounds). It doesn't matter what substance comprises the kilogram.

-- Although their weights are identical, any mass of feathers occupies more volume than the same mass of iron, no matter where they happen to be located.

-- Iron is more dense than feathers, and more dense than a lot of other substances as well, too.

7 0

3 years ago

A 75-hp (shaft output) motor that has an efficiency of 91.0 percent is worn out and is to be replaced by a high- efficiency moto

daser333 [38]

Convert the shaft ouput from HP to kW

Shaft output = 75HP = 55.93kW

1st: Finding for the power consumption based on 55.93kW output

Power consumption (Old) = 55.93kW / .910 = 61.46kW

Power consumption (New) = 55.93kW / .954 = 58.63kW

2nd: Total power used in kWh:

Power Used = Power consumption * load factor * Hours:

Power (Old) = 61.46kW * .75 * 4368 = 201343 kWh

Power (New) = 58.63kW * .75 * 4368 = 192072 kWh

Energy saved = 201343 kWh - 192072 kWh = 9,271 kWh

3rd: Calculating for the price:

Price = kW-Hr * $/kWh

Price (Old) = 201343kWh * $0.08/kWh = $16107.44

Price (New) = 192072 kWh * $0.08/kWh = $15365.76

Cost saved = $16107.44 - $15365.76 = $741.68/yr

4th: Setting up the cost equation:

Cost over time, F(t) = Motor_Cost + (Price * Number of Years, t)

Cost (Old) = 5449 + 16107.44*t

Cost (New) = 5520 + 15365.76*t

Equate the two to find for t when they cost equally:

5449 + 16107.44*t = 5520 + 15365.76*t

16107.44*t = 15365.76*t +71

16107.44*t - 15365.76*t = 71

741.68*t = 71

t = 71 / 741.68 = .095 years = 35 days

So the payback period is after 35 days.

6 0

3 years ago

An object experiences an acceleration of -6.8m/s^2. As a result, it accelerates from 54m/s to a complete stop. how much distance

Kipish [7]

Answer:

210 m

Explanation:

Given:

a = -6.8 m/s²

v₀ = 54 m/s

v = 0 m/s

Find: Δx

v² = v₀² + 2aΔx

(0 m/s)² = (54 m/s)² + 2 (-6.8 m/s²) Δx

Δx ≈ 210 m

6 0

3 years ago

A local FM radio station broadcasts at a frequency of 97.3 MHz. Calculate the energy of the frequency at which they are broadcas

levacccp [35]

Answer:

6.45×10¯²⁶ J

Explanation:

From the question given above, the following data were obtained:

Frequency (f) = 97.3 MHz

Energy (E) =?

Next, we shall convert 97.3 MHz to Hz. This can be obtained as follow:

1 MHz = 1×10⁶ Hz

Therefore,

97.3 MHz = 97.3 MHz × 1×10⁶ Hz / 1 MHz

97.3 MHz = 9.73×10⁷ Hz

Thus, 97.3 MHz is equivalent to 9.73×10⁷ Hz.

Finally, we shall determine the energy at which the frequency is broadcasting. This can be obtained as follow:

Frequency (f) = 9.73×10⁷ Hz

Planck's constant (h) = 6.63×10¯³⁴ Js

Energy (E) =?

E = hf

E = 6.63×10¯³⁴ × 9.73×10⁷

E = 6.45×10¯²⁶ J

Therefore, the energy at which the frequency is broadcasting is 6.45×10¯²⁶ J

5 0

3 years ago

Oil having a density of 924 kg/m 3 floats on water. A rectangular block of wood 3.79 cm high and with a density of 970 kg/m3 flo

Katena32 [7]

Answer:

x = 2.69 cm

Explanation:

We are given ;

Density of oil; ρ_oil = 924 kg/m³

Density of wood; ρ_wood = 970 kg/m³

h = 3.79cm

Density of water ( ρ_water) has a constant value of 1000 kg/m³

At equilibrium position, we have;

ρ_wood•g•h - ρ_oil•g•(h - x) - ρ_water•g•x = 0

This is because the density of oil is lower than that of water while density of wood is higher than that of oil but lower than that of water.

x is the distance below the interface between the two liquids is the bottom of the block.

Thus, let's make x the subject;

x = [(ρ_wood - ρ_oil)/(ρ_water - ρ_oil)] x h

Plugging in the relevant values to get ;

x = [(970 - 924)/(1000 - 924)] x 3.79

x = (54/76) x 3.79 = 2.69cm

5 0

4 years ago