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3 years ago

In real machines,efficiency is always

Physics

2 answers:

Monica [59]3 years ago

6 0

In real machines, efficiency is always less than 1 .

alukav5142 [94]3 years ago

4 0

Less than 100% Because from the moment it is built it begins to break down.

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Describe at least two ways that electromagnet force and weak nuclear forces are alike and two ways that they are different.

ruslelena [56]

Different: The weak nuclear force is responsible for radioactive decay within an atom of a substance, while the electromagnetic force causes electrostatic force between charged particles.

Different: The weak force has a very small range of effectiveness (where the force can be felt) while the electromagnetic force has an infinite range.

Same: Both forces act within an nucleus, or on a nuclear level.

Same: The weak nuclear force is mediated by charged particles called bosons, and the electrostatic force is only present within charged objects

The last one may be a bit of a stretch but I hope this helped a bit!

4 0

4 years ago

During a compaction test in the lab a cylindrical mold with a diameter of 4in and a height of 4.58in was filled. The compacted s

Ray Of Light [21]

Answer:

part a : The dry unit weight is 0.0616  $lb/in^3$ 

part b : The void ratio is 0.77

part c : Degree of Saturation is 0.43

part d : Additional water (in lb) needed to achieve 100% saturation in the soil sample is 0.72 lb

Explanation:

Part a

Dry Unit Weight

The dry unit weight is given as

$\gamma_{d}=\frac{\gamma}{1+\frac{w}{100}}$

Here

$\gamma_d$ is the dry unit weight which is to be calculated
γ is the bulk unit weight given as

$\gamma =weight/Volume \\\gamma= 4 lb / \pi r^2 h\\\gamma= 4 lb / \pi (4/2)^2 \times 4.58\\\gamma= 4 lb / 57.55\\\gamma= 0.069 lb/in^3$

w is the moisture content in percentage, given as 12%

Substituting values

$\gamma_{d}=\frac{\gamma}{1+\frac{w}{100}}\\\gamma_{d}=\frac{0.069}{1+\frac{12}{100}} \\\gamma_{d}=\frac{0.069}{1.12}\\\gamma_{d}=0.0616 lb/in^3$

The dry unit weight is 0.0616  $lb/in^3$ 

Part b

Void Ratio

The void ratio is given as

$e=\frac{G_s \gamma_w}{\gamma_d} -1$

Here

e is the void ratio which is to be calculated

$\gamma_d$ is the dry unit weight which is calculated in part a
$\gamma_w$ is the water unit weight which is 62.4 $lb/ft^3$ or 0.04 $lb/in^3$

G is the specific gravity which is given as 2.72

Substituting values

$e=\frac{G_s \gamma_w}{\gamma_d} -1\\e=\frac{2.72 \times 0.04}{0.0616} -1\\e=1.766 -1\\e=0.766$

The void ratio is 0.77

Part c

Degree of Saturation

Degree of Saturation is given as

$S=\frac{G w}{e}$

Here

e is the void ratio which is calculated in part b

G is the specific gravity which is given as 2.72

w is the moisture content in percentage, given as 12% or 0.12 in fraction

Substituting values

$S=\frac{G w}{e}\\S=\frac{2.72 \times .12}{0.766}\\S=0.4261$

Degree of Saturation is 0.43

Part d

Additional Water needed

For this firstly the zero air unit weight with 100% Saturation is calculated and the value is further manipulated accordingly. Zero air unit weight is given as

$\gamma_{zav}=\frac{\gamma_w}{w+\frac{1}{G}}$

Here

$\gamma_{zav}$ is the zero air unit weight which is to be calculated

$\gamma_w$ is the water unit weight which is 62.4 $lb/ft^3$ or 0.04 $lb/in^3$

G is the specific gravity which is given as 2.72

w is the moisture content in percentage, given as 12% or 0.12 in fraction

$\gamma_{zav}=\frac{\gamma_w}{w+\frac{1}{G}}\\\gamma_{zav}=\frac{0.04}{0.12+\frac{1}{2.72}}\\\gamma_{zav}=\frac{0.04}{0.4876}\\\gamma_{zav}=0.08202 lb/in^3\\$

Now as the volume is known, the the overall weight is given as

$weight=\gamma_{zav} \times V\\weight=0.08202 \times 57.55\\weight=4.72 lb$

As weight of initial bulk is already given as 4 lb so additional water required is 0.72 lb.

4 0

3 years ago

Gravity causes objects to be attracted to one another. This attraction keeps our feet firmly planted on the ground and causes th

aev [14]

Answer:

A) G = m³/kg.s²

B) E = kg.m²/s²

Explanation:

The given relation is:

F = Gm₁m₂/r²

where, the units of all variables are:

F = Force = kg.m/s²

m₁ = m₂ = mass = kg

r = distance = m

G = Gravitational Constant = ?

Therefore,

kg.m/s² = G(kg)(kg)/m²

(kg.m/s²)(m²/kg²) = G

G = m³/kg.s²

The given equation is:

E = mc²

where, the units of all variables are:

m = mass = kg

c = speed = m/s

E = Energy = ?

Therefore,

E = (kg)(m/s)²

E = kg.m²/s²

This is the correct answer, which is not present in any option.

4 0

4 years ago

If a big truck in front of your car begins to turn left, but its right turn signals are flashing, it is most likely that truck d

marissa [1.9K]

Its most likely C. Remember the bigger the vehicle the bigger the area it needs to make a safe turn.

5 0

3 years ago

Read 2 more answers

Does an eclipse occur every time the moon is in the new or full moon phase?

harina [27]

Answer:

solar eclipse mostly occurs when the moon gets between Earth and the sun, and the moon casts a shadow over Earth. A solar eclipse can only take place at the phase of new moon, when the moon passes directly between the sun and Earth and its shadows fall upon Earth's surface.

7 0

3 years ago

Read 2 more answers