What is conduction? Please help. First answer will mark Brainliest

Answer:

Explanation:

ave speed is always (frequency) x (wavelength)

Speed  =  (450 /sec) x (0.52 m)

=      234 m/sec .

Answer: There will be 75258 nuclei left at 6 pm.

Explanation:

a) half-life of the radioactive substance:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

[tex]t_{\frac{1}{2}}=\frac{0.69}{k}[/tex]

[tex]k=\frac{0.69}{t_{\frac{1}{2}}}=\frac{0.693}{2hours}=0.346hours^{-1}[/tex]

b) Expression for rate law for first order kinetics is given by:

[tex]A=A_0e^{-kt}[/tex]

where,

k = rate constant  

t = time for decomposition = 6 hours ( from 12 noon to 6 pm)

A = activity at time t = ?

[tex]A_0[/tex] = initial activity  = 600, 000

[tex]A=600000\times e^{-0.346\times 6}[/tex]

[tex]A=75258[/tex]

Thus there will be 75258 nuclei left at 6 pm.

Answer:

a. frequency = 25 Hz, period = 0.04 s , wave number = 19.63 rad/m

b. y = (0.0700 m)sin[(19.63 rad/m)x - (157.08 rad/s)t]

c.  0.0496 m

d. 0.03 s

Explanation:

a. Frequency, f = v/λ where v = wave speed = 8.00 m/s and λ = wavelength = 0.320 m

f = v/λ = 8.00 m/s ÷ 0.320 m = 25 Hz

Period, T = 1/f = 1/25 = 0.04 s

Wave number k = 2π/λ = 2π/0.320 m = 19.63 rad-m⁻¹

b. Using y = Asin(kx - ωt) the equation of a wave

where y = displacement of the wave, A = amplitude of wave = 0.0700 m and ω = angular speed of wave = 2π/T = 2π/0.04 s = 157.08 rad/s

Substituting the variables into y, we have

y = (0.0700 m)sin[(19.63 rad/m)x - (157.08 rad/s)t]

c. When x = 0.360 m and t = 0.150 s, we substitute these into y to obtain

y = (0.0700 m)sin[(19.63 rad/m)x - (157.08 rad/s)t]

y = (0.0700 m)sin[(19.63 rad/m × 0.360 m) - (157.08 rad/s × 0.150 s)]

y = (0.0700 m)sin[(7.0668 rad) - (23.562 rad)]

y = (0.0700 m)sin[-16.4952 rad]

y = (0.0700 m) × 0.7084

y = 0.0496 m

d. For the particle at x = 0.360 m to reach its next maximum displacement, y = 0.0700 m at time t. So,

y = (0.0700 m)sin[(19.63 rad/m)x - (157.08 rad/s)t]

0.0700 m = (0.0700 m)sin[(19.63 rad/m × 0.360 m) - (157.08 rad/s)t]

0.0700 m = (0.0700 m)sin[(7.0668 rad - (157.08 rad/s)t]  

Dividing through by 0.0700 m, we have

1 = sin[(7.0668 rad - (157.08 rad/s)t]

sin⁻¹(1) = 7.0668 rad - (157.08 rad/s)t  

π/2 = 7.0668 rad - (157.08 rad/s)t

π/2 - 7.0668 rad = - (157.08 rad/s)t

-5.496 rad = - (157.08 rad/s)t

t = -5.496 rad/(-157.08 rad/s) = 0.03 s

The frequency of the wave is 25 Hz, the period is 0.04 s, and the wave number of the given wave is 19.63 rad/m.

(A) Frequency of the wave,

[tex]\bold {f = \dfrac v{\lambda}}[/tex]

where

v - speed = 8.00 m/s

λ - wavelength = 0.320 m

[tex]\bold {f = \dfrac {8.0 m/s }{0.32\ m} = 25\ Hz}[/tex]

Period of the wave,

[tex]\bold {T = \dfrac 1f = \dfrac 1{25 } = 0.04\ s }[/tex]

Wave number of the wave,

[tex]\bold {k = \dfrac {2\pi }{\lambda} = \dfrac {2\pi }{0.320} = 19.63\ rad\ m^{-1}}[/tex]

(B)

Wave function equation of a wave,

y = A sin (kx - ωt)

where

y - displacement of the wave

A = amplitude  = 0.0700 m

ω = angular speed  = 2π/T = 2π/0.04 s = 157.08 rad/s

Put the values in the formula,

y = (0.0700 m)sin[(19.63 rad/m)x - (157.08 rad/s)t]

(C) When x = 0.360 m and t = 0.150 s,

y = (0.0700 m)sin[(19.63 rad/m × 0.360 m) - (157.08 rad/s × 0.150 s)]

y = 0.0496 m

Therefore, the frequency of the wave is 25 Hz, the period is 0.04 s, and the wave number of the given wave is 19.63 rad/m.

To know more about waves,

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Answer: find the answer in the explanation

Explanation:

1.) More thermal energy will be required to raise the temperature of 2 Kg of a substance by 10°C than is required to raise the temperature of 1 Kg of the same substance by 10°C. 

Because the thermal energy depends on the mass of an object.

If the two materials are the same, then they will have the same specific heat capacity. Thermal energy can be expressed as:

H = MCØ

Where

M = mass of the body

C = specific heat capacity

Ø = change in temperature

H = thermal energy

If u substitute the two values of masses into the formula above, then, the mass of 2kg will produce higher thermal energy .

Il.) Heat causes expansion. Using kinetic theory to explain this, the molecules of solid material are in a fixed pattern, held together with strong bonds. When heat is applied to the solid, the molecules will start vibrating in their fixed position. As a result of this, the bond between the molecules begins to loss. This eventually lead to expansion of solid.

Answer:

166 cm

Explanation:

Given :

d1 =109cm

M1= 45kg

M2=29000g = 29 kg

As we know that Newton second law

[tex]Force\ =\ Mass\ *\ Acceleration[/tex]

Here M1= 45kg  

and acceleration=[tex]9.81 m/s^{2}[/tex]

Therefore

[tex]F1=45 * 9.81[/tex]

[tex]F1= 441.45 N[/tex]

M2=29000g = 29 kg

Similarly

[tex]F2= 29 * 9.81\\ F2= 284.4 N[/tex]

Now we using the Principal of moments

[tex]F1 * d1 =F2 *d2[/tex]

[tex]441.5 * 109\ =\ 290\ *\ d2\\48,123.5=290 d2\\d2 =165.9[/tex]

~ d2=166 cm

Answer:

Henri’s wave and Geri’s wave have the same amplitude and the same energy

Explanation:

The amplitude of a wave is the distance between the midpoint and the trough (or the crest). This is equivalent to half the distance between the trough and the crest. Therefore:

The energy of a wave is directly proportional to its amplitude.

Answer:

its letter b

Explanation:

Answer:

They are the physical parts of a computer.

examples :monitor,keyboard,system unit and mouse.

Answer:

So the weight of the body is 700N

Explanation:

mass of the object=70kg

force of gravity=10N/kg

weight of the object=w-?

as we know that

weight=mass × force of gravity

weight=70kg × 10N/kg

WEIGHT OF THE BODY=700N

I HOPE IT WILL HELP YOU

GOOD LUCK FOR THE ASSIGNMENT

The correct answer is 700 N.

Object mass = 70 kg

Gravity = 10N / kg

Weight = Mass x Gravity

Weight = 70kg x 10N / kg

Weight = 700 N

Mass is more basic because it is a unique property of the object. Weight varies from place to place depending on the acceleration of gravity. If the mass on the earth is m = 10kg, the weight is W = mg = 10 x 10 = 100N.

The strength of the Earth's gravitational field is 10 Newtons (N / kg) per kilogram. This means that there is a force of 10 Newtons per kilogram on Earth. Mass is the amount of substance that makes up an object.

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Answer:

The maximum height that a cannonball fired at 420 m/s at a 53.0° angles is 5740.48m.

hmax = 5740.48 m

Explanation:

This is an example of parabolic launch. A cannonball is fired on flat ground at 420 m/s at a 53.0° angle and we have to calculate the maximum height that it reach.

V₀ = 420m/s and θ₀ = 53.0°

So, when the cannonball is fired it has horizontal and vertical components:

V₀ₓ = V₀ cos θ₀ = (420m/s)(cos 53°) = 252.76 m/s

V₀y = V₀ cos θ₀ = (420m/s)(cos 53°) = 335.43m/s

When the cannoball reach the maximum height the vertical velocity component is zero, that happens in a tₐ time:

Vy = V₀y - g tₐ = 0

tₐ = V₀y/g

tₐ = (335.43m/s)/(9.8m/s²) = 34.23s

Then, the maximum height is reached in the instant tₐ = 34.23s:

h = V₀y tₐ - 1/2g tₐ²

hmax = (335.43m/s)(34.23s)-1/2(9.8m/s²)(34.23s)²

hmax = 11481.77m - 5741.29m

hmax = 5740.48m

Answer:

The most of the elements in the periodic table are metals. The elements cannot be gases and liquids (Molecules are mainly gases and liquids). Metalloids are few. Examples (Germanium, Arsenic)

Answer:

Resultant force = (1.2 - 9.8m)ĵ N

where m = mass of the ball

Magnitude of the resultant force = (9.8m - 1.2) N

Since the weight of the ball is expected to exceed the air resistance (because the ball is falling vertically downwards), the direction of the resultant force is vertically downwards. Its unit is Newtons, the SI unit of Force.

Explanation:

If a ball is falling vertically downwards, the only two forces acting on the ball include the weight of the ball (the pull of gravity on the ball) and the air resistance on the ball.

Weight of the ball acts downwards and is given as mg. where m = mass of the ball and g is the acceleration due to gravity = 9.8 m/s²

W = mg = (9.8m) N

In vector form, W = (-9.8mĵ) N

The air resistance on the ball = 1.2 N, the air resistance acts in the direction opposite the motion of the ball, and since the ball is moving vertically downwards, the air resistance acts vertically upwards.

In vector form, the air resistance = (1.2ĵ) N

Hence, the resultant force acting on the ball is the vector sum of all the forces acting on the ball.

Resultant force = (-9.8mĵ) + (1.2ĵ)

= (1.2 - 9.8m)ĵ N

Since the weight of the ball is expected to exceed the air resistance (because the ball is falling vertically downwards), the direction of the resultant force is vertically downwards.

Hope this Helps!!!

Answer:

(a) 3.22 m

(b) The vertical velocity, [tex]v_y[/tex], at maximum height is 0 m/s, the horizontal velocity, vₓ, is 12.72 m/s

(c) The acceleration at maximum height = g = 9.81 m/s²

(d) The time it takes for the paper to reach the balcony is 1.212 seconds

(e) The horizontal range, of the paper is 15.42 m.

Explanation:

(a) Given that we re given a projectile motion, we have the following governing equations;

y = y₀ + v₀·sin(θ₀)·t - 0.5×g·t²

[tex]v_y[/tex] = v₀·sin(θ₀) - g·t

Where:

y = Height of the paper

y₀ = Initial height of the paper = Ground level = 0

v₀ = Inititial velocity of the paper = 15.0 m/s

θ₀ = Angle in which the paper is thrown = 32° above the horizontal

g = Acceleration due to gravity = 9.81 m/s²

t = Time taken to reach the height h

[tex]v_y[/tex] = Vertical velocity of the paper

At maximum height, [tex]v_y[/tex] = 0, therefore;

[tex]v_y[/tex] = v₀·sin(θ₀)·t - g·t = 0

v₀·sin(θ₀) = g·t

t = v₀·sin(θ₀)/g = 15×sin(32°)/9.81 = 0.81 seconds

y = y₀ + v₀·sin(θ₀)·t - 0.5×g·t² = 0 + 15×sin(32°)×0.81-0.5×9.81×0.81² = 3.22 m

(b) The vertical velocity, [tex]v_y[/tex], at maximum height = 0 m/s, the horizontal velocity, vₓ, = 15×cos(32°) = 12.72 m/s

(c) The acceleration at maximum height = g = 9.81 m/s²

(d) The time it takes to maximum height = 0.81 seconds

The time the paper will take to fall to 1.25 m above the ground, which is 3.22 - 1.25  = 1.97 meters below maximum height is therefore given as follows;

y = y₀ + v₀·sin(θ₀)·t - 0.5×g·t²

Where:

v₀ = 0 m/s at maximum height

y = -1.97 m downward motion

y₀ = 0 starting from maximum height downwards

1.97 = 0 + 0·sin(θ₀)·t - 0.5×9.81×t²

-1.97 =  - 0.5×9.81×t²

t = (-1.97)/(-0.5*9.81) = 0.402 seconds

The time the paper will take to fall to 1.25 m above the ground = 0.81+0.402 = 1.212 seconds

Therefore, the time it takes for the paper to reach the balcony = 1.212 seconds

(e) The horizontal range, x, is given by the relation;

x = x₀ + v₀·cos(θ₀)·[tex]t_{tot}[/tex]

x₀ = Starting point of throwing the paper = 0

[tex]t_{tot}[/tex] = Total time of flight of the paper

∴ x = x₀ + v₀·cos(θ₀)·[tex]t_{tot}[/tex] = 0 + 15×cos(32°)×1.212 = 15.42 m

The horizontal range, of the paper = 15.42 m.

Answer:

There must be an equal amount of each element on both sides of the equation. Hope this helps and please marks as the brainliest.

Explanation:

Answer:

The answer is D

Explanation:

Hope this helps!

Answer:

400grams

Explanation:

Mass is density × volume

0.5×800= 400 grams

Mass is density × volume

0.5×800= 400 grams.

Density is the number of things—which could be people, animals, plants, or objects—in a certain area. To calculate density, you divide the number of objects by the measurement of the area. The population density of a country is the number of people in that country divided by the area in square kilometers or miles.

density, the mass of a unit volume of a material substance. The formula for density is d = M/V, where d is density, M is mass, and V is volume.

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Answer:

the answers the correct one is: the time increases

Explanation:

When an insulating material is placed in the cavity of a wall the thermal conductivity of the system increases, therefore the temperature changes take longer.

             P= dQ / dt = K A dT / dx

when placing insulation the value of k is less

When reviewing the answers the correct one is: the time increases

Answer:

A - 4.5 m/s

Explanation:

31,500/7,000= 4.5

Answer:

the speed is 3m/s

Explanation:

below is the working

Answer:

Total contraction on the Bar  = 1.22786 mm

Explanation:

Given that:

Total Length for aluminum bar = 600 mm  

Diameter for aluminum bar  = 40 mm

Hole diameter  = 30 mm

Hole length = 100 mm

elasticity for the aluminum is 85GN/m² = 85 × 10³ N/mm²

compressive load P = 180 KN = 180  × 10³ N

Calculate the total contraction on the bar = ???

The relation used in  calculating the contraction on the bar is:

[tex]\delta L = \dfrac{P *L }{A*E}[/tex]

The relation used in  calculating the total contraction on the bar can be expressed as :

Total contraction in the Bar = (contraction in part of bar without hole + contraction in part of bar with hole)

i.e

Total contraction on the Bar = [tex]\dfrac{P *L_1 }{A_1*E} + \dfrac{P *L_2 }{A_2 *E}[/tex]

Let's find the area of cross section without the hole and with the hole

Area of cross section without the hole is :

Using A = πd²/4

A = π (40)²/4

A = 1256.64 mm²

Area of cross section with the hole is :

A = π (40²-30²)/4

A = 549.78 mm²

Total contraction on the Bar = [tex]\dfrac{P *L_1 }{A_1*E} + \dfrac{P *L_2 }{A_2 *E}[/tex]

Total contraction on the Bar  = [tex]\dfrac{180 *10^3 \N }{85*10^3 \ N/mm^2} [\dfrac{500}{1256.64}+ \dfrac{100}{549.78}][/tex]

Total contraction on the Bar  = 2.117( 0.398 + 0.182)

Total contraction on the Bar  = 2.117*(0.58)

Total contraction on the Bar  = 1.22786 mm

Answer: The material that is not a mixture; it has the same properties all the way through is called a substance.

Explanation:

A pure substance is a form of matter that has a constant composition and properties that are constant throughout the sample. Hence, it cannot be separated by physical means. Example: Gold

Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. They can be separated by physical means as well. Example: Air

Thus the material that is not a mixture; it has the same properties all the way through is called a substance.

Answer:

R = -2500N

Explanation:

Use formula ΣF = Ma. We can split the Net Force into two parts: Fe - Ff  =  Ma.

Fe is the force developed by the engine: 4000N

Ff (R) is the air resistance projected on the vehicle. This is the value we're looking for.

Mass: 1000kg

Acceleration: 1.5m/s^2

Next, just plug in the values and solve.

▪4000N - Ff  =  (1000kg)(1.5m/s^2)

▪Ff = 1500N - 4000N

▪Ff = -2500N

R = -2500N.

The air resistance acting on the car is R = -2500N.

Note that the correct times are t = 0, t = 1/4, t = 1/2. You can tell from the spaces between the two digits. i.e 1&4 and 1&2

Answer:

y(0) = 2.00 cm

y(1/4) = 1.56 cm

y(1/2) = 1.21 cm

Explanation:

This is a very simple exercise, the displacement of the oscillating weight from equilibrium has already been modeled by the equation:

[tex]y(t) = 2e^{-t} cos 4t[/tex]

Where y = displacement ( in cm)

and t = time (in seconds)

The task is to find the displacement when t = 0, 1/4 and 1/2

When t = 0 s

[tex]y(0) = 2e^{0} cos 4(0)\\y(0) = 2* 1*1\\y(0) = 2.00 cm[/tex]

When t = 1/4 s

[tex]y(1/4) = 2e^{-1/4} cos 4(1/4)\\y(14) = 2e^{-1/4} cos (1)\\y(1/4) = 1.56 cm[/tex]

When t = 1/2

[tex]y(1/2) = 2e^{-1/2} cos 4(1/2)\\y(14) = 2e^{-1/2} cos (2)\\y(1/2) = 1.21 cm[/tex]

Answer:

Explanation:

For the block placed on the table, there are several force acting on the body along the horizontal and vertical axis. All this forces tends to keep the body in a state of equilibrium.The forces acting along the horizontal are the moving force (Fm) and the frictional force (Ff).

Frictional force are forces that acts opposite to the force that causes the body to move (moving force).

If Lien uses a spring scale to pull a block toward the right across the lab table and the scale reads 8 N, this means that the force that causes the body to move is the 8N force (moving force).

Taking the sum of force along the horizontal;

[tex]\sum fx = ma_x[/tex]

Since the body is static, max = 0

[tex]\sum fx = 0\\fm+(-Ff)= 0[/tex]

Note that the frictional force acts is the force of opposition acting in the negative x direction.

[tex]fm = 0+Ff\\fm = Ff[/tex]

Since Fm = 8N, Ff will also be equal to 8N.

Based on the above proof, Lien can also conclude that 8 N is a frictional force

The loudness of sound is inversely proportional to the square of the distance of the listener from the source. (B)

Answer:

B. It is inversely proportional to the square of the distance of the listener from the source.

Explanation:

Answer:

(a) =34.0J

(b) = 13.038m/s

(c) =

Explanation:

(a) mass (m) =0.45kg

Height(h) =8.5m

Gravity (g) =10m/s^2

But P. E (Potential Energy) = mass × gravity × height

P. E = 0.45×10×8.5

P. E = 34.0J

(b) using v^2=u^2 - 2gs

Where v = final velocity

u= initial velocity

g = gravity

s =distance

But at maximum height v =0

0^2= u^2 - 2gs

Transpose u^2 we have

u^2 = 2gs

u^2 = 2×10×8.5

u^2 = 170

u = square root of 170

u = 13.038m/s

Answer:

When a body is moving on a circle it is accelerating because centripetal acceleration is always acting on it towards the center.

Please see the attached picture...

From the above diagram,we can say the acceleration is always acting on the body when it moves in a circle.

Hope this helps.......

Good luck on your assignment.......

Answer:

an object moving in uniform circular motion is moving in a circle with a uniform or constant speed. The velocity vector is constant in magnitude but changing in direction. Because the speed is constant for such a motion, many students have the misconception that there is no acceleration. "After all," they might say, "if I were driving a car in a circle at a constant speed of 20 mi/hr, then the speed is neither decreasing nor increasing; therefore there must not be an acceleration." At the center of this common student misconception is the wrong belief that acceleration has to do with speed and not with velocity. But the fact is that an accelerating object is an object that is changing its velocity. And since velocity is a vector that has both magnitude and direction, a change in either the magnitude or the direction constitutes a change in the velocity. For this reason, it can be safely concluded that an object moving in a circle at constant speed is indeed accelerating. It is accelerating because the direction of the velocity vector is changing.

Explanation: hopes it help u

Answer:

2.25 m

50 N

Explanation:

Given :

[tex]m=10 g=0.01 kg[/tex]

Initial velocity =U= [tex]150 \ ms^{-1}[/tex]

[tex]Time=t=0.03\ s[/tex]

Final velocity =v=0

We know that

[tex]V=U + at[/tex]

[tex]a\ =\ \frac{V-U}{t}[/tex]

Putting the value of V,U and t in the previous equation we get

[tex]a=\frac{0-150}{0.03} \ \\a=-5000 ms^{-2}[/tex]

According the second law of motion

[tex]s=Ut+\frac{1}{2} *\ at^{2}[/tex]

Putting the value of U,t and a we get

[tex]s=150\ *\ 0.03\ +\frac{1}{2} \ *(-5000)\ * 0.03\ *0.03\\s=2.25\ m[/tex]

We know that

[tex]F=mass * acceleration\ \\F=0.01 * 5000\ \\F=50 N[/tex]

Answer:

Potential energy = mass × gravity × height

= m × g × h

mass = 5 kg

height = 4m

g= 10m/s²

Potential energy = 5 × 10 × 4

= 200Joules

Hope this helps.

Answer:

The reason is because the pressure of the air inside the room drops with time which makes opening the door to require an increased amount of force to make up for the reduced pressure inside the room

Explanation:

From the kinetic theory of gases we have the following relation;

[tex]v_{rms} = \sqrt{\dfrac{3 \cdot K \cdot T}{m} }[/tex]

[tex]p = \dfrac{n \cdot MW \cdot v^2_{rms} }{3 \cdot V}[/tex]

Where:

K = Boltzmann constant

T = Temperature

m = Mass

MW = Molecular weight

V = Volume

[tex]v_{rms}[/tex] = Root mean square velocity

Whereby the room door is closed, the kinetic energy of the air particles will be used up such that the average velocity of the particles will decrease, given that the volume of the room is constant, the pressure inside the room will drop below the original pressure outside the room such that the force on the door due to the outside pressure is larger than the force on the door from inside the room requiring a larger amount of force to overcome the resistance of the now higher outside pressure force.

Answer:

This galaxy belongs to the elliptical galaxy category. This is because it does not have spiral arms.

Answer:

The substances which allow an electric current to pass through it is called conductors.

Example: Metals like copper,iron ,graphite etc.

The substances which do not allow the electric current to pass through is called Insulators.

Example: Glass, dry wood ,plastic etc.

Hope this helps...

Good luck on your assignment...