Enter the expression 2cos2(θ)−1 , where θ is the lowercase Greek letter theta.

The three ways a car can accelerate are change in velocity, change in direction, or both.

The rate of velocity change concerning time is known as acceleration. The acceleration of the object is;

[tex]\rm a = \frac{v-u}{t}[/tex]

Here,

a is the acceleration

v is the final velocity

u is the initial velocity

t is the period

The three ways a car can accelerate are as follows;

a)Change in velocity.

b)Change in direction

c)Change in both velocity and direction.

Hence, the three ways a car can accelerate are change in velocity, change in direction, or both.

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Answer:

The critical radius of the plastic insulation is 0.72 inches.

Explanation:

Given that,

Diameter = 0.091 in

Thickness = 0.02 in

Initial temperature = 90°F

Final temperature = 50°F

Heat transfer coefficient = 2.5 Btu/h.ft²°F

Material conductivity = 0.075 Btu/h.ft °F

We need to calculate the critical radius of the plastic insulation

Using formula of critical radius

[tex]r_{cr}=\dfrac{2K}{h}[/tex]

Where, k = Material conductivity

h = Heat transfer coefficient

Put the value into the formula

[tex]r_{cr}=\dfrac{2\times0.075}{2.5}[/tex]

[tex]r_{cr}=0.06\ ft[/tex]

[tex]r_{cr}=0.72\ inches[/tex]

Hence, The critical radius of the plastic insulation is 0.72 inches.

Answer:

C. Muddy Water

Answer:

(a) , .  and .

(b)[tex]\vec A - \vec C=22 \hat i -10 \hat j[/tex].

(c)[tex]|\vec A - \vec B|=63.13[/tex] and the direction [tex]\theta =[/tex] 124.56°.

Explanation:

Given that,

,

and

[tex]\vec {C}=2 \hat i +43 \hat j[/tex]

(a) The magnitude of a vector is the square root of the sum of the square of all the components of the vector, i.e. for a ,.

So, the magnitude of the is

[tex]|\vec A|=\sqrt {24^2+ 33^2}[/tex]

[tex]\Rightarrow |\vec A|=\sqrt {1665}[/tex]

.

The magnitude of the is

[tex]|\vec B|=\sqrt {55^2+ (-12)^2}[/tex]

[tex]\Rightarrow |\vec B|=\sqrt {3169}[/tex]

.

And, the magnitude of the is

[tex]|\vec C|=\sqrt {2^2+ 43^2}[/tex]

[tex]\Rightarrow |\vec C|=\sqrt {1853}[/tex]

.

(b) The difference between the two vectors is the difference between the corresponding components of the vectors. So, the required expression of is

[tex]\vec A - \vec C=(24 \hat i +33 \hat j) - (2 \hat i +43 \hat j)[/tex]

[tex]\Rightarrow \vec A - \vec C=24 \hat i +33 \hat j - 2 \hat i -43 \hat j[/tex]

[tex]\Rightarrow \vec A - \vec C=22 \hat i -10 \hat j[/tex]

(c) The expression of is

[tex]\vec A - \vec N=(24 \hat i +33 \hat j) - (55 \hat i -12 \hat j)[/tex]

[tex]\Rightarrow \vec A - \vec B=24 \hat i +33 \hat j - 55\hat i +12 \hat j[/tex]

[tex]\Rightarrow \vec A - \vec B=-31 \hat i +45 \hat j\;\cdots (i)[/tex]

The magnitude of is

[tex]|\vec A - \vec B|=\sqrt {(-31)^2+55^2}[/tex]

[tex]\Rightarrow |\vec A - \vec B|=\sqrt {3986}[/tex]

[tex]\Rightarrow |\vec A - \vec B|=63.13[/tex]

Now, if a vector [tex]\vec V= -\alpha \hat i +\beta \hat j[/tex] in 3rd quadrant having direction [tex]\theta[/tex] with respect to [tex]\hat i[/tex] direction, than

in the anti-clockwise direction.

Here, from equation (i), for the vector [tex]\vec A - \vec C[/tex], [tex]\alpha=31[/tex] and [tex]\beta=45[/tex].

[tex]\Rightarrow \theta = \pi-\tan ^{-1}\left(\frac {45}{31}\right)[/tex]

180°-55.44° [as \pi radian= 180°]

124.56° in the anti-clockwise direction.

(d) Vector diagrams for [tex]\vec A +\vec B[/tex] and [tex]\vec A - \vec B[/tex] has been shown  

in the figure(b) and figure(c) recpectively.

Vector [tex]\vec A - \vec B[/tex] is in 3rd quadrant as calculated in part (c).

While Vector [tex]\vec A +\vec B=(24 \hat i +33 \hat j)+(55 \hat i -12 \hat j)[/tex]

[tex]\Rightarrow \vec A +\vec B=79 \hat i +21 \hat j[/tex], which is in 1st quadrant as both the components are position has been shown in figure(b).

Answer: rotational force

Explanation:

Torque is the twisting force which cause rotation and the axis of rotation is the point at which the object rotates.

Torque is a rotational force as it leads to the rotation of an object about an axis. Force simply means a pull or push. When an unbalanced ball acts on a force, the ball, the ball will be moved towards the linear motion.

Then, the unbalanced force that is acting in the ball produces torque which causes the ball's rotational motion.

The Torque is best described as a rotational force.

It is the force that causes an object to rotate. Torque is measured in Newton-meters (N-m).

An example of a force is the force of gravity. When you hold a ball in your hand, the force of gravity is pulling down on the ball.

However, the ball is not rotating because the force of gravity is being counteracted by the force of your hand pushing up on the ball.

An example of a torque is when you use a wrench to loosen a bolt. When you apply force to the wrench, you are creating a torque that is trying to turn the bolt.

The more force you apply, the greater the torque.

Torque is not the same as rotational velocity. Rotational velocity is the rate at which an object is rotating. It is measured in radians per second (rad/s).

Torque is also not the same as rotational energy.

Rotational energy is the energy that an object has due to its rotation.

It is measured in joules (J).

Torque is also not the same as rotational power. Rotational power is the rate at which rotational energy is transferred. It is measured in watts (W).

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Answer:

Explanation:

If Two cylindrical resistors are made from the same material, then their resistivity will be the same.  Formula for calculating resistivity of a material is expressed as;

[tex]\rho = \frac{RA}{L} \ where \ A = \frac{\pi d^2}{4}[/tex] where;

R is the resistance

A is the cross sectional area of the material

L is the length of the material

For the shorter cylinder:

Length = L

diameter = D

[tex]\rho = \dfrac{R_s(\frac{\pi D^2}{4})}{L} \\\\\rho = \dfrac{R_s{\pi D^2}}{4L}[/tex]

For the longer cylinder:

Length = 16L

diameter = 4D

[tex]\rho = \dfrac{R_l(\frac{\pi (4D)^2}{4})}{16L} \\\\\\\rho = \dfrac{R_l(\frac{\pi (16D^2)}{4})}{16L} \\\\\rho = \dfrac{R_l{16\pi D^2}}{16L}\\\\\rho = \dfrac{R_l{\pi D^2}}{L}[/tex]

Since their resistivity are the same then;

[tex]\dfrac{R_s{\pi D^2}}{4L} = \dfrac{R_l{\pi D^2}}{L} \\\\ \dfrac{R_s}{4} = {R_l} \\\\R_s = 4R_l\\\\R_l = \frac{R_s}{4}[/tex]

Hence the resistance of the longer resistor is a quarter of the shorter resistor.

Answer:

The value is [tex]D = 205.8 \ m [/tex]

Explanation:

The time taken for the column to take a step mathematically represented as

100 steps => 1 minutes => 60 seconds

1 step => t

=> [tex]t = 0.6 \ s [/tex]

Generally the length of the column is mathematically represented as

[tex]D = v * t[/tex]

substituting 343 m/s for v we have

        [tex]D =  343 * 0.6 [/tex]

  =>    [tex]D =  205.8 \  m  [/tex]

Answer:

5000 m/s

Explanation:

Answer:

The value is [tex]v_s = 1.394 \ m/s[/tex]

Explanation:

From the question we are told that

The frequency of the second player is [tex]f_2 = 490 \ Hz[/tex]

The beat frequency is [tex]f_b = 2.0 \ Hz[/tex]

The speed of sound is [tex]v_s = 343 \ m/s [/tex]

Generally the frequency of the note played by the first player is mathematically represented as

[tex]f_1 = f_2 + f_b[/tex]

=> [tex]f_1 = 490 + 2.0 [/tex]

=> [tex]f_1 = 492 Hz[/tex]

From the relation of Doppler Shift we have that

[tex]f_1 = \frac{ f_2 (v+ v_o )}{v-v_s }[/tex]

Here [tex] v_o\ is\ the\ velocity\ of\ the\ observer\ with\ value\ 0 \ m/s [/tex]

So

[tex]492 = \frac{ 490 (343+0 )}{343 -v_s }[/tex]

=> [tex]v_s = 1.394 \ m/s[/tex]

Answer:

a)  I = 0.0198 kg m² ,  b)    I = 21.85 kg m²

Explanation:

For this exercise we will use the definition of moment of inertia

        I = ∫ r² dm

For body with high symmetry they are tabulated

sphere  I = 2/5 m r²

bar with respect to  center of mass I = 1/12 m L²

let's calculate the mass of each body

bar

        ρ = m / V

        m = ρ V

        m = ρ l w h

where we are given the density of the bar rho = 32840 kg / m³ and its dimensions 1 m, 0.8 cm and 4 cm

        m = 32820 1 0.008 0.04

        m = 10.5 kg

Sphere

       M = ρ V

       V = 4/3 pi r³

       M = rgo 4/3 π r³

give us the density 37800 kg / m³ and the radius of 5 cm

       M = 37800 4/3 π 0.05³

       M = 19.8 kg

a) asks us for the moment of inertia of the sphere with respect to its center of mass

        I = 2/5 M r²

        I = 2/5 19.8 0.05²

        I = 0.0198 kg m²

b) the moment of inertia with respect to the turning point, for this we will use the theorem of parallel axes

        I = I_cm + M d2

where d is the distance from the body to the point of interest

        I_cm = 0.0198 kg m²

the distance to the pivot point is

        l = length of the bar + radius of the sphere

        l = 1 + 0.05 = 1.005 m

        I = 0.0198 + 19.8 1.05²

        I = 21.85 kg m²

Answer: Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. ... During the 1930s Bohr helped refugees from Nazism.

Answer:

10 miles per minute.

Answer:

i think gravity created a force strong enough to push him down.but it also depends how slow or fast the bus is going

Explanation:

gravity as we all now it is pretty strong so if the bus is going fast then the person standing up will fall but if the bus is going pretty slow then it'll just nudge him.

Answer:

   ρ = 4.4 10⁻⁸ Ω m

Explanation:

For this exercise let's start by finding the value of the resistance using Ohm's law

          V = I R

           R = V / I

The voltage is related to the electric field

          V = E L

let's substitute

          R = E L / I

          R = 8.2 10⁻² / 20  

          R = 4.1 10⁻³ L

now we can use the resistance relation

          R = ρ L / A

the area of ​​a circular wire is

          A = π r² = π d² / 4

         ρ = R π d² / (4 L)

let's calculate

        ρ = (4.1 10⁻³ L) π 0.0037² / (4 L) = (4.1 10⁻³) π 0.0037² / (4)

        ρ = 4.4 10⁻⁸ Ω m

The resistivity of the wire is 4.4 10⁻⁸ Ω m.

We know that;

V = I R

R = V / I

The voltage  the electric field can be connected using the formula;

V = E L

Hence;

R = E L /I

R = 8.2 10⁻² / 20  

R = 4.1 10⁻³ L

For resistivity;

R = ρ L / A

the area can be obtained from;

A = π r² = π d² / 4

ρ = R π d² / (4 L)

ρ = (4.1 10⁻³ L) π 0.0037² / (4 L) = (4.1 10⁻³) π 0.0037² / (4)

ρ = 4.4 10⁻⁸ Ω m

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The Answer Is - 0.58 Kilogram's

Hope This Help's

• Answer:

0.58 kg

• Explanation:

1 kg = 1000 g

580 g = 0.58 kg

Answer:

44 years

Explanation:

Use half life equation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is time,

and T is the half life.

0.25 A₀ = A₀ (½)^(t / 22)

0.25 = (½)^(t / 22)

t / 22 = 2

t = 44

44 sec is half life of a given sample of radium is 22 years the sample will reduce to 25% of its original value.

The period of time it takes for one-half of a radioactive isotope to decay is known as the half-life. A given radioactive isotope's half-life is constant; it is unaffected by external factors and independent of the isotope's starting concentration.

Use half life equation:

A = A₀ (½)^(t / T)

where A is the final amount,

A₀ is the initial amount,

t is time,

and T is the half life.

0.25 A₀ = A₀ (½)^(t / 22)

0.25 = (½)^(t / 22)

t / 22 = 2

t = 44 sec

44 sec is half life of a given sample of radium is 22 years the sample will reduce to 25% of its original value.

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Answer:

The hight of the building is 38.16 m

Explanation:

These two pieces of information given, first, the watermelon is 30 m  above the ground and after 1.50 s the watermelon has been spotted. Now we are required to find the height of the building.

Use the below formula to find the height of buildings.

S = ut + ½ gt^2

30  =1.5u + (1/2) × 9.8 (1.5)^2

u = 12.65 m/sec

v^2 – u^2 = 2gs

(12.65)^2 = 2×9.8 s’

S’ = 8.16 m  

h = s + s’

h = 30 + 8.16 = 38.16 m

The hight of the building is 38.16 m.

The height of the building is 38.16 m.

Given data:

The height above the ground is, h = 30.0 m.

The time interval after observation of first spot is, t = 1.50 s.

We need to find the height of building. And since two pieces of information given, first, the watermelon is 30 m  above the ground and after 1.50 s the watermelon has been spotted. So, using the second kinematic equation of motion as,

[tex]h = ut + \dfrac{1}{2}gt^{2}[/tex]

Here, u is the initial speed. Solving as,

[tex]30 = (u \times 1.50) + \dfrac{1}{2} \times 9.8 \times (1.50)^{2}\\\\u =12.65 \;\rm m/s[/tex]

Now landing distance (s') is calculated using the third kinematic equation of motion as,

[tex]v^{2} =u^{2}+2(-g)s\\\\0^{2} =12.65^{2}+2(-9.8)s\\\\s = 8.16 \;\rm m[/tex]

Then the height of building is given as,

H = h + s

H = 30 m + 8.16 m

H = 38.16 m

Thus, we can conclude that the height of the building is 38.16 m.

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Answer:

F=200N

a=500m/s2​

Mass=?

Explanation:

F=ma

200=m*500

200/500=m

Mass=0.4kg

Answer:

0.0552 m/s²

Explanation:

Given:

Δx = 69.0 m

v₀ = 0 m/s

t = 50 s

Find: a

Δx = v₀ t + ½ at²

69.0 m = (0 m/s) (50 s) + ½ a (50 s)²

a = 0.0552 m/s²

Answer:

t=8

Explanation:

u have solution I give solution also

don't mark plzz follow y

Explanation:

13+x=43>2x

13+x=43>2x+43>2x

13+x=86>4x

x-4x=86-13

3x=73

x=73/3

x=24.333

x=24.4

Answer:

B

Explanation:

because when the air rises the density increases

We want to predict what will happen to the density of the air on the surface of the Earth when it warms up.

We will see that the correct option is D: "It decreases, then increases"

We know that the temperature of a given object (in this case a mass of air) is related to the kinetic energy of the particles that conform it.

As the temperature increases, the kinetic energy also increases, thus, the amount of motion of each particle increases, thus, the volume of the object increases.

Now remember that:

density = Mass/Volume.

So if the volume of something increases, we will see that the density decreases (as the volume is in the denominator).

Then if the temperature of the air increases, we will see that the density of the air in the surface decreases.

But it does not end there, as only the air near the surface suffers this change of density, we will have a denser mass of air (colder air) above it. And because it is denser (has more mass in the same volume) we can say that it is heavier.

Then eventually the hot air will rise, and the cold air will fall down, thus the density of the air in the surface increases again, as the colder and denser air comes near the surface.

This is one way of how wind currents are born.

Concluding we can see that the correct option is D: "It decreases, then increases"

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Answer:

FALSE

Explanation:

Answer:

im going between 2 of them b and c but i would have choose b

Answer:

Hello!

Sorry you haven't put up an image of your question! Without it we can't answer your question!

Explanation:

Maybe put up another one and it'll be answered!

:D