12. By convention (agreement of the scientific community for consistency)
magnetic field lines...

A. always start on the north pole and terminate (end) on the South Pole

B. start at infinity and point toward each pole

C. start at each pole and go outward

D. always start on the south pole and terminate (end) on the north pole.

Answer:

the car movves briefly as you ran, however, it stops again after you ran in to the wall

Explanation:

Our net total linear momentum was zero at the time both the train and the boy was at rest. As there is no pressure, the train and boy system's linear momentum can be conserved provided no external forces are working on it that might shift its momentum.

If the boy runs inside of the train with a velocity V1 in the forward direction, the train would have a velocity V2 in the reverse direction to V1 to conserve the system's momentum, resulting in Final momentum.

i.e

[tex]m \times V_1 + M \times V_2 = 0[/tex]  --- (1)

here;

m = mass of the boy

M = mass of the train

Thus;

[tex]m \times V_1 =- M \times V_2[/tex] --- (2)

As the boy crashes into the train's wall, a pair of equal and opposing force F intervene on both the train and the boy. This force F causes the boy traveling with momentum m× V1 to come to a halt; its momentum remains zero. As the train moves with about the same momentum as the boy as seen in (2) and is subjected to the same force F, its momentum will be diminished to zero, and it will come to a halt.

Answer:

Waves carry energy from one place to another.

Explanation:

Because waves carry energy, some waves are used for communication, eg radio and television waves and mobile telephone signals.

Answer:

v = -17.94 cm

Explanation:

Given that,

The candle is placed at a distance of 50 cm, u = -50 cm

The focal length of the diverging lens, f = -28 cm (negative in case of a concave lens)

We need to find the image distance. We know that the lens formula is as follows:

[tex]\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}\\\\\dfrac{1}{v}=\dfrac{1}{f}+\dfrac{1}{u}\\\\\dfrac{1}{v}=\dfrac{1}{(-28)}+\dfrac{1}{(-50)}\\\\v=-17.94\ cm[/tex]

So, the image distance is equal to 17.94 cm.

Answer:

C

Explanation:

The men bow to the women and the women curtsy to the men.

(took on test and got it right)

Answer:

Gravity

Explanation:

Gravity pulls things down to earth and it is a force

Answer:

C

Explanation:

C

Answer:

The work down on satellite X by the force in terms of Kx is [tex]\dfrac{-K_x}{4}[/tex].

Explanation:

The work done is given as in terms of

[tex]W=\Delta TE[/tex]

Where ΔTE is the change in total energy.

This is given as

[tex]W=\Delta TE\\W=TE_y-TE_x\\W=\dfrac{-GMm}{2(4R)}-\dfrac{-GMm}{2(3R)}\\W=\dfrac{-GMm}{8R}+\dfrac{GMm}{6R}\\W=\dfrac{-6GMm+8GMm}{48R}\\W=\dfrac{2GMm}{48R}\\W=\dfrac{GMm}{24R}[/tex]

Rearranging it in  terms of K_x gives

[tex]W=\dfrac{GMm}{24R}\\W=\dfrac{GMm}{-4\times -6R}\\W=\dfrac{1}{-4}\dfrac{-GMm}{6R}\\W=\dfrac{1}{-4}\dfrac{-GMm}{2(3R)}\\W=\dfrac{1}{-4}K_x\\W=\dfrac{-K_x}{4}[/tex]

Answer:

W = F * S = 300 N * 30 m = 9000 Joules

This is the work out of the system regardless of how the pulleys are arranged

Conservation of energy tells that

Work Out = Work In - Work done by friction

So Work In = 9000 J + 2000 J = 11000 J      The work input to the system

Explanation:

The answer is In the picture. Thanks.

Answer:

The box will not move from its position.

Explanation:

First, we will calculate the static frictional force that is stopping the box to move from its position:

[tex]f = \mu R = \mu W=\mu mg[/tex]

where,

f = static frictional force = ?

μ = coefficient of static friction = 0.3

m = mass of box = 4 kg

g = acceleration due to gravity = 9.81 m/s²

Therefore,

[tex]f = (0.3)(4\ kg)(9.81\ m/s^2)\\f=11.77\ N[/tex]

Since the frictional force (11.77 N) is greater than the applied force (10 N).

Therefore, the box will not move from its position.

Answer:

Mechanical waves are waves that require a medium. This means that they have to have some sort of matter to travel through. These waves travel when molecules in the medium collide with each other passing on energy. One example of a mechanical wave is sound.

Answer:

By talking about something that interesto you’

sorry if wrong

Explanation:

Answer:

B : using a spring scale and measuring the weight of the car

Explanation:

Answer:

Eroding

Explanation:

A long time ago on top of a mountain, the rocks were jagged and pointy. Over thousands of years, the rocks have become smooth. The process explains this change is Eroding. Hence, Option D is the correct answer.

Erosion is  a  process  of  eroding some solids by wind, water and other  natural  agent  while  weathering  is  breaking  down  of  rocks, soil  and  minerals.

The  different types of Erosion includes,

These factors that will contribute to the rate of water erosion includes the climatic factor (rainfall amount, intensity and frequency).

Mass wasting erosion if it is a type of erosion but not by water. It is a type of erosion that is generated mainly by the effect of gravity. It is also called mass movement, in which the material detaches from an inclined surface and falls as a result of gravity.

Here, A long time ago on top of a mountain, the rocks were jagged and pointy. Over thousands of years, the rocks have become smooth. The process explains this change is Eroding. Hence, Option D is the correct answer.

Learn more about Erosion,

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Answer: 84 %

Explanation:

Answer:

[tex]0.3165\ \text{rad/s}[/tex]

Explanation:

m = Mass of person = 65 kg

d = Diameter of round table = 6.5 m

r = Radius = [tex]\dfrac{d}{2}=3.25\ \text{m}[/tex]

v = Velocity of person running = 3.8 m/s

[tex]I_t[/tex] = Moment of inertia of turntable = [tex]1850\ \text{kg m}^2[/tex]

Moment of inertia of the system is

[tex]I=I_t+mr^2\\\Rightarrow I=1850+65\times 3.25^2\\\Rightarrow I=2536.5625\ \text{kg m}^2[/tex]

As the angular momentum of the system is conserved we have

[tex]L_i=L_f\\\Rightarrow mvr=I\omega_f\\\Rightarrow \omega_f=\dfrac{mvr}{I}\\\Rightarrow \omega_f=\dfrac{65\times 3.8\times 3.25}{2536.5625}\\\Rightarrow \omega_f=0.3165\ \text{rad/s}[/tex]

The angular velocity of the turntable is [tex]0.3165\ \text{rad/s}[/tex].

Answer:

huh

Explanation:

Answer:

Time taken by Mr. smith = 4.80 hour (Approx.)

Explanation:

Given:

Distance travel by Mr. smith = 523 kilometer

Average speed of Mr. smith = 109 km/hr

Find;

Time taken by Mr. smith

Computation:

Time taken = Distance cover / Speed

Time taken by Mr. smith = Distance travel by Mr. smith / Average speed of Mr.

smith

Time taken by Mr. smith = 523 / 109

Time taken by Mr. smith = 4.798 hr

Time taken by Mr. smith = 4.80 hour (Approx.)

Answer:

3 i think

Explanation:

Answer:

[tex]0.0018833\ \text{m/s}[/tex]

Explanation:

[tex]d[/tex] = Distance of Andromeda Galaxy from Earth = [tex]2.54\times 10^7\ \text{ly}[/tex]

[tex]t[/tex] = Time taken = [tex]90\ \text{years}[/tex]

[tex]c[/tex] = Speed of light = [tex]3\times 10^8\ \text{m/s}[/tex]

We have the relation

[tex]t=t_o\sqrt{1-\dfrac{v^2}{c^2}}\\\Rightarrow 90=2.54\times 10^7\sqrt{1-\dfrac{v^2}{c^2}}\\\Rightarrow \dfrac{90^2}{(2.54\times 10^7)^2}=1-\dfrac{v^2}{c^2}\\\Rightarrow 1-\dfrac{90^2}{(2.54\times 10^7)^2}=\dfrac{v^2}{c^2}\\\Rightarrow v=c\sqrt{1-\dfrac{90^2}{(2.54\times 10^7)^2}}[/tex]

[tex]c-v=c(1-\sqrt{1-\dfrac{90^2}{(2.54\times 10^7)^2}})\\\Rightarrow c-v=3\times 10^8(1-\sqrt{1-\dfrac{90^2}{(2.54\times 10^7)^2}})\\\Rightarrow c-v=0.0018833\ \text{m/s}[/tex]

The required answer is [tex]0.0018833\ \text{m/s}[/tex].

Answer:

It will bob 7.887640449 times a minute

Explanation:

I hope this is correct!!

Answer:

Collision theory is used to predict the rates of chemical reactions, particularly for gases. It is based on the assumption that for a reaction to occur for the reacting species (atoms or molecules) must come together or collide with one another. Not all collisions, however, bring about chemical change.

If two molecules collide with sufficient activation energy, there is no guarantee that the collision will be successful. In fact, the collision theory says that not every collision is successful, even if molecules are moving with enough energy. The reason for this is because molecules also need to collide with the right orientation so that the proper atoms line up with one another, and bonds can break and re-form necessarily.

you haven't attached the diagram, but i assume that this diagram is what you were talking about

Answer:

near Y

Explanation:

the electric field lines goes from a positive charge to a negative charge. This means that a positive charge would move in the same direction of the field lines, while a negative charge would move in the opposite direction of the field lines. the field lines are created from +vely charged plate to -vely charged plate so the negative charged particles moves towards the lower plate which is positively charged, and opposite to the direction of field lines.

The charge will most likely leave the electric field near Y letter. Hence option C is correct.

Electric charge is the physical property of matter that experiences force when it is placed in electric field. F = qE where q is amount of charge, E = electric field and F = is force experienced by the charge. there are two types of charges, positive charge and negative charge which are generally carried by proton and electron resp. like charges repel each other and unlike charges attract each other. the flow charges is called as current. Elementary charge is amount of charge a electron is having, whose value is 1.602 x 10⁻¹⁹ C

The charge on the electron is negative, and the force is directed in the opposite direction as the electric field. When an electron is projected perpendicular to a uniform electric field, it experiences an electric force in the opposite direction of the field.

the trajectory of the charged particle in the electric filed is parabolic and in magnetic field it is circular. when this electron moves perpendicular to the electric field, electron experience force in opposite direction to the electric field and due to parabolic nature, it will leave at Y.

Hence option C is correct.

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Answer:

[tex]\triangle x=1.135 *10^9km[/tex]

Explanation:

From the question we are told that:

Diameter of array[tex]d=6000km \approx 6000*10^3[/tex]

Infrared wavelength [tex]\lambda =10m[/tex]

Distance of planet [tex]d=59 light\ years \approx 55.82*10^{16}m[/tex]

Generally the equation for Diffraction is mathematically given by

 [tex]sin\theta =1.22\frac{\lambda}{D}[/tex]

Given that

 [tex]sin\theta=\frac{\triangle x}{R}[/tex]

Therefore

 [tex]\frac{\triangle x}{R}=1.22\frac{\lambda}{D}[/tex]

 [tex]\triangle x=1.22\frac{R \lambda}{D}[/tex]

 [tex]\triangle x=1.22\frac{10 *55.82*10^{16}}{6000*10^3}[/tex]

 [tex]\triangle x=1.135 *!0^1^2m[/tex]

 [tex]\triangle x=1.135 *10^9km[/tex]

hydroelectric dam converts the potential energy stored in a water reservoir behind a dam to mechanical energy—mechanical energy is also known as kinetic energy. ... The generator converts the turbine's mechanical energy into electricity.

Hope this helps!

Answer:

Potential energy and kinetic energy are constituents of mechanical energy.

When a turbine is switched on, it rotates with mechanical energy.

Since a motor runs the turbine, it converts this mechanical energy to electrical energy.

Answer:

a)   y = 3.73 m,  b)  t = 1.74 s,  c)  R = 40.99 m,

d) vₓ  = 23.49  m/s,   v_y = -8.5 m / s

Explanation:

This is a projectile launching exercise, we start by breaking down the initial velocity

          sin θ = v_{oy} / v₀

          cos θ = v₀ₓ / v₀

          v_{oy} = v₀ sin θ

          v₀ₓ = v₀ cos θ

          v_{oy} = 25 sin 20 = 8.55 m / s

          v₀ₓ = 25 cos 20 = 23.49 m / s

a) when the egg reaches the maximum height its vertical speed is zero

          v_y² = v_{oy}² - 2 g y

          0 = v_[oy}² - 2g y

           y = v_{oy}² / 2g

          y = [tex]\frac{8.55^2}{2 \ 9.8 }[/tex]

          y = 3.73 m

b) flight time

          y = v_{oy} t - ½ g t²

the time of flight occurs when the body reaches the ground y = 0

          0 = (v_{oy} - ½ g t) t

The results are

          t₁ = 0s        this time is for using the body star

          v_{oy} - ½ g t = 0

           t = [tex]\frac{2v_{oy}^2}{g}[/tex]

           t = 2 8.55 / 9.8

           t = 1.74 s

c) the range

           R = v₀² sin 2θ / g

           R = 25² sin (2 20) / 9.8

           R = 40.99 m

d) speed at the point of arrival

horizontal speed is constant

           vₓ = v₀ₓ = 23.49  m/s

vertical speed is

           v_y = Iv_{oy} - g t

           v_y = 8.55 - 9.8  1.74

           v_y = -8.5 m / s

Answer:

a). 1.28333 seconds

b). 186.66 seconds

Explanation:

a). Given :

Distance between the earth and the moon, d = [tex]$3.85 \times 10^8$[/tex] m

Speed of the radio waves, c = [tex]$3 \times 10^8$[/tex] m/s

Therefore the time required for the voice of Neil Armstrong to reach the earth via radio waves is given by :

[tex]$t=\frac{d}{c}$[/tex]

 [tex]$=\frac{3.85 \times 10^8}{3 \times 10^8}$[/tex]

 = 1.28333 seconds

b). Distance between Mars and the earth, d = [tex]$5.6 \times 10^{10}$[/tex] m

   Speed of the radio waves, c = [tex]$3 \times 10^8$[/tex] m/s

So, the time required for his voice to reach earth is :

[tex]$t=\frac{d}{c}$[/tex]

 [tex]$=\frac{5.6 \times 10^{10}}{3 \times 10^8}$[/tex]

 = 186.66 seconds

Answer:

1) m = 0.3137 kg

2a)T_f = -181.7°C

2b) T_f = -1176.97°C

Explanation:

1) We are given;

Length; l = 4.30 cm = 0.043 m

Width; w = 14.0 cm = 0.014 m

height; h = 27.0 cm = 0.027 m

density of gold; ρ = 19.3 × 10³ kg/m³

Formula for the density is known as;

ρ = mass/volume

Thus;

m =ρV

m = 19.3 × 10³ × (lwh)

m = 19.3 × 10³ × (0.043 × 0.014 × 0.027)

m = 0.3137 kg

2a) We are given;

Diameter of brass; L_br = 10 cm

Diameter of aluminum; L_al = 10.01 cm

Now, to some for change in temperature we will use the formula;

L_f = L_i + αL_i(Δt)

Where α is coefficient of expansion.

Now, for the ring to be removed from the rod, the final diameter of the brass has to be same as the aluminium.

Thus;

L_f(brass) = L_f(aluminium)

From table attached, α_brass ≈ 19 × 10^(-6) /°C

Also, α_aluminium ≈ 24 × 10^(-6) /°C

Thus;

L_f(brass) = 10 + (19 × 10^(-6) × 10 × (Δt))

Similarly,

L_f(aluminium) = 10.01 + (24 × 10^(-6) × 10.01 × (Δt))

Since L_f(brass) = L_f(aluminium), then;

10 + (19 × 10^(-6) × 10 × (Δt)) = 10.01 + (24 × 10^(-6) × 10.01 × (Δt))

Rearranging, we have;

10.01 - 10 = (19 × 10^(-6) × 10 × (Δt)) - (24 × 10^(-6) × 10.01 × (Δt))

0.01 = Δt(-50.24 × 10^(-6))

Δt = 0.01/(-50.24 × 10^(-6))

Δt ≈ -199°C

Thus, temperature at which the combination must be cooled to separate the two metals is;

T_f = T_i + Δt

T_f = 17.3 + (-199)

T_f = -181.7°C

2b) Diameter of aluminum is now;

L_al = 10.06 cm

Thus;

10.06 - 10 = (19 × 10^(-6) × 10 × (Δt)) - (24 × 10^(-6) × 10.01 × (Δt))

0.06 = Δt(-50.24 × 10^(-6))

Δt = 0.06/(-50.24 × 10^(-6))

Δt = -1194.27°C

T_f = 17.3 + (-1194.27)

T_f = -1176.97°C