A piece of wood from a nearby construction site floats near the shore of a lake. It floats in very calm water with half of its volume just above the surface. What is the density of this piece of wood

Answer:

0.78m/s^2

Explanation:

using the third equation of motion, the answer is found

v^2=u^2 -2gs

where V= 0 at the maximum point

2gs=u^2

g=u^2

2s

g=2.5^2

2(4)

g=0.78125m/s^2

or g=0.78m/s^2

We are given:

Homer the Astronaut:

Mass of Homer the astronaut(m1) = 200 kg

initial velocity of Homer the astronaut(u1) = 5 m/s

Larry the Pal:

Mass of Larry the Pal (m2) = 150 kg

initial velocity of Larry the Pal (u2) = 0 m/s

Since they will move together after the collision, they will have the same velocity:

v1 = v2 = V

Solving for the Final velocity:

from the law of conservation of momentum:

m1u1 + m2u2 = m1v1 + m2v2

since v1 = v2 = V:

m1u1 + m2u2 = V(m1 + m2)

replacing the variables with the given values

200 * 5 + 150 * 0 = V(200 + 150)

1000 = 350V

V  = 1000 / 350

V = 2.86 m/s

It is the proportion predicted to be present in the early universe.

The hydrogen and helium abundance helps us to model the expansion rate of the early universe.

In the abundance of hydrogen and helium, we can say that they account for nearly all the nuclear matter in today's universe.

In big Bang model, the universe is mostly light or protons.

The Schramm's model for relative abundances indicate that helium is about 25% by mass and hydrogen about 73% with all other elements constituting less than 2%.

Several proponents of big Bang theory has proposed similar relative abundance for hydrogen and helium. In all  it is clear that hydrogen and helium constitute of more than 98% of the ordinary matter in the universe.

Finally, the hydrogen and helium abundance helps us to model the expansion rate of the early universe.

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Answer: i think its c but i am not sure tho but i think its she could replace the 6 v battery with a 12 v battery

Explanation: cause a 12 v is stronger than a 6 v battery

A student made the electromagnet shown and used it to pick up one sewing pin. She then doubled the number of coils around the nail and used it to pick up two sewing pins. She could replace the 6V battery with a 12 V battery.

Permanent magnets are not the same as electromagnets. Coils of wire with electricity running through them make up electromagnets. An electromagnet's wire coils act like magnets when an electric current flows through them because moving charges produce magnetic fields.

The coils stop functioning as a magnet when the electricity is turned off. A lot of things use electromagnets.

When magnetic forces are only required for brief periods of time, electromagnets are frequently used in electrical equipment.

Therefore, A student made the electromagnet shown and used it to pick up one sewing pin. She then doubled the number of coils around the nail and used it to pick up two sewing pins. She could replace the 6V battery with a 12 V battery.

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Answer:

B. symbolic

Explanation:

The mental image formed in Terell's mind is a symbolic mental image.

A symbolic mental image helps to bring perception to imagery formed on the mind.

Answer:

Terell lives in Washington, D.C., where he can see the Potomac River from his bedroom window. When he sees this river, Terell thinks of swimming, boating, fun, and friends. What type of mental image is this?

symbolic

Explanation:

The force required to hold it completely submerged under water is 0.252 N

As a result of the low density (ρ1 = 0.0839 g/cm3 = 83.9 kg/m3)of the ball compared to that of water (ρ2 =1000 kg/m3), the buoyant force that is acting on the ball is greater than its weight.

Therefore, the minimum force required to hold the ball submerged under water can be calculated using the relation

Radius = 3.77/2 cm = 0.0377/2 m = 0.01885 m

Volume of sphere = 4/3 π r³ = 4/3 * 3.142 * 0.01885³ = 2.805 e-5 m³

Mass of sphere = 4/3 π r³ ρ1 = 4/3 * 3.142 * 0.01885³ * 83.9 = 0.0023 kg

Weight of sphere = 4/3 π r³ ρ1 g = 4/3 * 3.142 * 0.01885³ * 83.9 * 9.8 = 0.023 N

Volume of water displaced = 4/3 π r³ = 2.805 e-5

Buoyant force = weight of water displaced = 4/3 π r³ ρ2 g = 4/3 π r³ = 4/3 * 3.142 * 0.01885³ * 1000 * 9.8 = 0.275 N

F = 0.275 - 0.023 = 0.252 N

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The force required to hold it completely submerged under water is 0.25 N

The density of the ball ([tex]\rho_b[/tex]) = 0.0839 g/cm³ = 83.9 kg/m³

The density of water [tex]\rho_w[/tex] = 1000 kg/m³

Diameter = 3.77 cm = 0.0377 m

radius of ball = 0.0377/2 = 0.01885 m

The volume (V) = [tex]\frac{4}{3} \pi r^3=\frac{4}{3}*\pi*0.01885^3=2.8*10^{-5}\ m^3[/tex]

Let us assume the acceleration due to gravity (g) = 9.8 m/s², Hence:

The force is required to hold it completely submerged under water (F) is:

[tex]F=\rho_w Vg-\rho_b Vg=1000*(2.8*10^{-5})*9.81-83.9*(2.8*10^{-5})*9.81\\\\[/tex]

F = 0.25 N

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Answer:

speed = 72.75km/hr

Explanation:

Let us first determine the Kinetic energy (KE) of the 18000kg truck

[tex]KE = \frac{1}{2} mv^2\\where:\\m = mass = 18000\\v = velocity = 21km/hr\\\therefore KE = \frac{1}{2} \times 18000 \times (21)^2\\= 9000 \times 441\\KE = 3,969,000\ Joules\\= 3,969\ KJ[/tex]

Next we will substitute this value of kinetic energy into the KE equation for the 1500kg compact car

[tex]KE = \frac{1}{2} mv^2\\3969000 = \frac{1}{2} \times 1500 \times v^2\\3969000 = 750 \times v^2\\v^2 = \frac{3969000}{750} = 5292\\v = \sqrt{5292} \\v = 72.75km/hr[/tex]

The speed at which the 1500 kg compact car have the same kinetic energy as the truck is 73 km/h

The kinetic energy of an object is known to be the energy at work and in motion. It is usually expressed as;

[tex]\mathbf{K.E = \dfrac{1}{2}mv^2}[/tex]

To determine the speed at which the car will have the same kinetic energy as the truck, we can say that:

[tex]\mathbf{\implies \dfrac{1}{2}m_c v_c^2= \dfrac{1}{2}m_t v_t^2}[/tex]

∴

[tex]\mathbf{\implies \dfrac{1}{2}\times 1500\times v_c^2= \dfrac{1}{2}\times 18000 \times 21^2}[/tex]

[tex]\mathbf{v_c^2= \dfrac{3969000}{ 750}}[/tex]

[tex]\mathbf{v_c^2=5292}[/tex]

[tex]\mathbf{v_c=\sqrt{5292}}[/tex]

[tex]\mathbf{v_c\simeq 73 km/h}[/tex]

Therefore, we can conclude that the speed at which the 1500 kg compact car have the same kinetic energy as the truck is 73 km/h

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Answer:

b

Explanation:

i took the test

Earth’s landmasses were first recognized as the continents we know today

135 million years ago.

Landmass is defines as a large area of land. It can also be referred to as the

continents we have today. There are seven types of earth landmasses and

they are

They were first discovered around 135 million years ago by the early

dwellers of the earth.

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When you turn off your bedroom lights, the kitchen lights can stay on. This is because your home is wired by using the series circuit. Hence, option B is correct.

The amount of current in the flow circuits of each element in a series circuit is the same. This is due to the recent flow having a single path. The flow rate (marble speed) at any point in a circuit (tube) at any given moment in time has to be equal because electric current moves through a conductor like marble in a duct.

The requirement that all values (voltage, current, resistance, and power) relate to one another in terms of the identical two places in a circuit is a significant exception to Ohm's law.

Therefore, the wiring of the home is in series combination. So, option B is correct.

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Answer:

False

Explanation:

Answer:

False

Explanation:

Hope this helped, Have a Wonderful Day/Night!!

Answer:

they are cooler than the rest if the sun

Answer: Work done is  - 501.56 J

Explanation:

Given that;

External pressure P = 15.0 atm

Volume V1 = 0.120 liters

Volume V2 = 0.450 liters

Work done = ?

we know that; Work = -Pdv

where P is pressure and dv is change in volume

so we substitute our values into the equation

Work = -15.0 × ( 0.450 - 0.120)

= -15 × 0.33

= - 4.95 atm/L

we know that;

1 atm.L = 101.325 J

so

- 4.95 atm/L = 101.325 J × -4.95 atm/L ÷

= - 501.56 J

Therefore Work done is  - 501.56 J

Answer:

work

Explanation:

Answer:

A

Explanation:

Answer:

350 N

Explanation:

Newton's second law:

∑F = ma

∑F = (175 kg) (2 m/s²)

∑F = 350 N

Answer:

Brittleness

Explanation:

Lustrous means shiny

sonorous means capable of producing a deep or ringing sound

and iron isn't brittle or weak

Answer:

[tex]\huge\boxed{\sf brittleness}[/tex]

Explanation:

Iron is a metal which have luster (shine) so it is lustrous (shiny).

Iron is sonorous. When it is hit with a hard object, it produces ringing sounds.

Iron is not brittle. It cannot be easily broken. So, Iron does not show brittleness (It cannot be easily broken)

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

Answer: True

Explanation: When light is reflected off lets say a mirror it is bent and changes direction to bounce off of another wall or object. For example if you take a flash light and shine it into a mirror the light reflects into a different direction your welcome

When light is reflected, the incident rays return back in straight direction and never bends and make the material gleaming. Hence, the statement is false.

Reflection is the phenomenon that, when waves incident on a material it returns back in straight direction. Both sound wave and light wave can be reflected. But, lightwaves are only reflected from transparent materials.

Reflection of light ray  make the material surface gleaming like in a mirror. Similarly reflection of sound waves produces echos. The phenomenon in which the light wave bends in its direction when moving from one medium to the other is called refraction.

The measure of bending of light in a medium is called the refractive index of that medium. Hence, bending of light is not reflection and it is termed as refraction. Thus, the statement is false.

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Answer:

(a) V₂ = 1.86 m/s

(b) Q = 5.1 x 10⁻⁴ m³/s

Explanation:

(a)

The formula derived for Venturi tube is as follows:

P₁ - P₂ = (ρ/2)(V₂² - V₁²)

where,

P₁ - P₂ = Difference in Pressure of Inlet and Outlet = 1.2 KPa = 1200 Pa

ρ = Density of Gasoline = 7.4 x 10² kg/m³

V₂ = Exit Velocity = ?

V₁ = Inlet Velocity

Therefore,

1200 Pa = [(7.4 x 10²kg/m³)/2](V₂² - V₁²)

V₂² - V₁² = (1200 Pa)/(3.7 x 10² kg/m³)

V₂² - V₁² = 3.24 m²/s²   ------------------- equation (1)

Now, we will use continuity equation:

A₁V₁ = A₂V₂

where,

A₁ = Inlet Area = πd₁²/4 = π(0.0374 m)²/4 = 1.098 x 10⁻³ m²

A₂ = Exit Area = πd₂²/4 = π(0.0187 m)²/4 = 2.746 x 10⁻⁴ m²

Therefore,

(1.098 x 10⁻³ m²)V₁ = (2.746 x 10⁻⁴ m²)V₂

V₁ = (2.746 x 10⁻⁴ m²)V₂/(1.098 x 10⁻³ m²)

V₁ = 0.25 V₂  

using this value in equation (1):

V₂² - (0.25 V₂)² = 3.24 m²/s²

0.9375 V₂² = 3.24 m²/s²

V₂² = (3.24 m²/s²)/0.9375

V₂ = √(3.456 m²/s²)

V₂ = 1.86 m/s

(b)

For fluid flow rate we use the following equation:

Flow Rate = Q = A₂V₂ = (2.746 x 10⁻⁴ m²)(1.86 m/s)

Q = 5.1 x 10⁻⁴ m³/s

The formula for finding variables in a  Venturi tube is shown below:

P₁ - P₂ = (ρ/2)(V₂² - V₁²)

where, P₁ - P₂ is difference in pressure of Inlet and outlet, ρ = density, V₂ = exit velocity and V₁ is inlet velocity

P₁ - P₂ = 1.2 KPa = 1200 Pa

ρ = 7.4 x 10² kg/m³

V₂ = Exit Velocity = ?

V₁ = Inlet Velocity

We then substitute the variables into this equation.

P₁ - P₂ = (ρ/2)(V₂² - V₁²)

1200 Pa = [(7.4 x 10²kg/m³)/2](V₂² - V₁²)

V₂² - V₁² = (1200 Pa)/(3.7 x 10² kg/m³)

V₂² - V₁² = 3.24 m²/s²  ------ equation (1)

The  continuity equation A₁V₁ = A₂V₂ is then used

where,A₁ = Inlet area = πd₁²/4 = π(0.0374 m)²/4 = 1.098 x 10⁻³ m²

A₂ = Exit Area = πd₂²/4 = π(0.0187 m)²/4 = 2.746 x 10⁻⁴ m²

(1.098 x 10⁻³ m²)V₁ = (2.746 x 10⁻⁴ m²)V₂

V₁ = (2.746 x 10⁻⁴ m²)V₂/(1.098 x 10⁻³ m²)

V₁ = 0.25 V₂  

We then substitute the value into equation 1

V₂² - (0.25 V₂)² = 3.24 m²/s²

0.9375 V₂² = 3.24 m²/s²

V₂² = (3.24 m²/s²)/0.9375

V₂ = √(3.456 m²/s²)

V₂ = 1.86 m/s

This can be calculated using the formula

Flow Rate = Q = A₂V₂

                  = (2.746 x 10⁻⁴ m²)(1.86 m/s)

                 = 5.1 x 10⁻⁴ m³/s

Solution:

The relation between the potential difference and the electric field between the plates of the parallel plate capacitor is given by :

[tex]$E=\frac{V}{D}$[/tex]

Differentiating on both the sides with respect to time, we get

[tex]$\frac{dE}{dt}=\frac{1}{D}\frac{dV}{dt}$[/tex]

Therefore, the rate of the electric field changes between the plates of the parallel plate capacitor is given by :

[tex]$\frac{dE}{dt}=\frac{1}{D}\frac{dV}{dt}$[/tex]

      [tex]$=\frac{1}{1.4 \times 10^{-3}} \times 110$[/tex]

      [tex]$=7.85 \times 10^4$[/tex]  V/m-s

precisely which regions?

Answer:

Romans have ruled for 450 years

Explanation:

Answer:

leon

Explanation:

leom ofjfjbfbfdnns

Answer:

46 J

Explanation:

Simply calculate the 92% of 50 Joules as:

0.92 * 50 J = 46 J

Answer:

Explanation:

Coordinate system is one that describe the location of an object in a given plane. It implies the use of axes (coordinates) and points.

Given that the man in the question walks 400 m due north of east. The cardinal points can be used in this case, with the north and east cardinals as the required axis.

scale = [tex]\frac{length on drawing}{original length}[/tex]

         = [tex]\frac{10}{400}[/tex]

         = [tex]\frac{1}{40}[/tex]

scale = 1:40

This is a reduced scale which implies that 1 cm on the drawing is equal to 40 m on the original length.

The man's direction is [tex]45^{o}[/tex] north of east.

The graphical drawing of the vector is herewith attached to this answer.

Answer:

Watt

Explanation:

Power is defined as the work done by an object per unit time. Its mathematical form is given by :

[tex]P=\dfrac{W}{t}[/tex]

The SI unit of work done is Joules (J) and that of time is seconds (s).

J/s is equal to watts. Watt is the metric unit of power.

Answer:

The total thermal energy required  is 8.93 Kcal

Explanation:

Given;

mass of the ice cube, m = 43 g

specific heat capacity of water, Cp = 4.18 J/gc

specific latent heat of fusion of ice, Cf = 334 J/g

First step, determine the heat needed to raise the temperature of the ice from -16.5 °C to 0° C

Q₁ = mCp[0 - (-16.5)]

Q₁ = 43 x 4.18(16.5)

Q₁ = 2965.71 J

Second step, determine the latent heat of fusion of ice at 0°C

Q₂ = mCf

Q₂ = 43 x 334

Q₂ = 14362 J

Third step, determine the quantity of heat required to raise the temperature of the water initially at 0°C to above 11.5 °C of boiling point of water.

The final temperature of the water = 11.5 °C + 100° C = 111.5 °C

Q₃ = mCp Δθ

Q₃ = 43 x 4.18 (111.5 - 0)

Q₃ = 20041 J

Total thermal energy required = Q₁ + Q₂ + Q₃

Total thermal energy required =  2965.71 J + 14362 J +  20041 J

Total thermal energy required = 37,368.71 J

Total thermal energy required = 8.93 Kcal

Answer:

[tex]\mid \vec C\mid=31.9[/tex]

Explanation:

Consider the vectors:

[tex]\vec A=9.4\mathbf{\hat{i}}-3.6\mathbf{\hat{j}}[/tex]

[tex]\vec B=-9.5\mathbf{\hat{i}}-13.4\mathbf{\hat{j}}[/tex]

Calculate the magnitude of

[tex]\vec C=-2\vec B-\vec A[/tex]

Substitute the values of the vectors:

[tex]\vec C=-2(-9.5\mathbf{\hat{i}}-13.4\mathbf{\hat{j}})-(9.4\mathbf{\hat{i}}-3.6\mathbf{\hat{j}})[/tex]

Operate and remove parentheses:

[tex]\vec C=19\mathbf{\hat{i}}+26.8\mathbf{\hat{j}}-9.4\mathbf{\hat{i}}+3.6\mathbf {\hat{j}}[/tex]

Operating both components separately:

[tex]\vec C=9.6\mathbf{\hat{i}}+30.4\mathbf{\hat{j}}[/tex]

Now find the magnitude of C:

[tex]\mid \vec C\mid=\sqrt{9.6^2+30.4^2}[/tex]

[tex]\mid \vec C\mid=\sqrt{1016.32}[/tex]

[tex]\mathbf{\mid \vec C\mid=31.9}[/tex]

Answer:

[tex]3.24\times 10^{-7}\ \text{m}[/tex]

Explanation:

m = Mass of bullet = 4.8 g

v = Velocity of bullet = 170 m/s

B = Magnetic field of Earth = [tex]5\times 10^{-5}\ \text{T}[/tex]

q = Charge of bullet = [tex]1.06\times 10^{-8}\ \text{C}[/tex]

a = Acceleration

Time the bullet will be in the air for is [tex]t=\dfrac{1000}{170}=5.88\ \text{s}[/tex]

Force is given by

[tex]F=ma[/tex]

Magnetic force is given by

[tex]F=qvB[/tex]

So

[tex]ma=qvB\\\Rightarrow a=\dfrac{qvB}{m}\\\Rightarrow a=\dfrac{1.06\times 10^{-8}\times 170\times 5\times 10^{-5}}{4.8\times 10^{-3}}\ \text{m/s}^2[/tex]

From the linear equations of motion we have

[tex]s=ut+\dfrac{1}{2}at^2\\\Rightarrow s=0+\dfrac{1}{2}\times \dfrac{1.06\times 10^{-8}\times 170\times 5\times 10^{-5}}{4.8\times 10^{-3}}\times 5.88^2\\\Rightarrow s=3.24\times 10^{-7}\ \text{m}[/tex]

The defelection of the bullet is [tex]3.24\times 10^{-7}\ \text{m}[/tex]

Answer:

How long do you jump (sec) ?

Explanation: