if you rub a balloon on your hair, it becomes charged, and as a result It can stick to your head without being held there. why doesn't it fall on the ground?

Answer:

i. Distance covered is 12 kilometres.

ii. Her displacement is 8.6 kilometres.

Explanation:

Distance is a span of length between two points, while displacement is the distance moved in a specified direction. Distance is a scalar quantity, while displacement is a vector.

She drives 7 kilometres north, then 5 kilometres east later.

i. Distance covered = 5 + 7

                                 = 12

Her distance covered is 12 kilometres.

ii. To determine her displacement, apply the Pythagoras rule to the sketch of her journey.

[tex]x^{2}[/tex] = [tex]5^{2}[/tex] + [tex]7^{2}[/tex]

   = 25 + 49

   = 74

x = [tex]\sqrt{74}[/tex]

  = 8.6023

Thus, her displacement is 8.6 kilometres.

Answer:

two of them in series with one in parallel

Explanation:

When two or more batteries are connected in

(a) series: the total voltage produced is equal to the sum of the voltages on each of the batteries. For example, if two batteries A and B of 3V and 2V respectively are connected in series, then the total voltage produced is

3V + 2V = 5V

(b) parallel: the total voltage produced is equal to the voltage on any one of the batteries. As a mention, only batteries of the same voltage should be connected together in parallel. For example, if two batteries A and B each of 4V are connected together in parallel, then the total voltage produced is 4V.

If these batteries are not of the same voltage, then the one of larger voltage will charge the one of the lower voltage until they both have the same voltage. That means that their eventual voltage will be the average of their voltages. For example, if two batteries A and B of 3V and 2V respectively, are connected in parallel, their total voltage will be,

(3V + 2V) / 2 =2.5V

Now, from the question.

Since there are three cells each of value 2V.

=>If we connect two of them in series, the total voltage from those two cells will be 2V + 2V = 4V

=>If we then connect this series connection in parallel with the third cell, then we have a parallel combination of 4V and 2V. Since they have different voltages, then the total voltage will be the average of the two voltages. i.e

(4V + 2V) / 2 = 6 / 2 = 3V

Therefore, to have a total of 3V from three cells each of 2V, we need to connect two of them in series with one in parallel

Answer:

i. the wavelength is 7.2 m

ii. the wavelength is 2.4 m

Explanation:

the wavelength of a wave is from crest to crest or from trough to trough.

Answer:

pressure=force/area

Answer:

0.12 kg

Explanation:

The amount of energy added is:

1000 W × (5 min × 60 s/min) = 300,000 J = 300 kJ

Heat to boil the water is:

q = mCΔT + mL

q = m (CΔT + L)

300 kJ = m (4.2 kJ/kg/K × (100°C − 30°C) + 2200 kJ/kg)

300 kJ = m (2494 kJ/kg)

m = 0.12 kg

Answer:

The time it will take for the object to hit the ground will be 4.

Explanation:

You have:

h(t)=−16t²+v0*t+h0

Being v0 the initial velocity (54 ft/s) and  h0 the initial height (40 ft) and replacing you get:

h(t)=−16t²+54*t+40

To know how long it will take for the object to touch the ground, the height h(t) must be zero. So:

0=−16t²+54*t+40

Being a quadratic function or parabola: f (x) = a*x² + b*x + c, the roots or zeros of the quadratic function are those values ​​of x for which the expression is 0. Graphically, the roots correspond to the points where the parabola intersects the x axis. To calculate the roots the expression is used:

[tex]\frac{-b+-\sqrt{b^{2}-4*a*c } }{2*a}[/tex]

In this case you have that:

Replacing in the expression of the calculation of roots you get:

[tex]\frac{-54+\sqrt{54^{2}-4*(-16)*40 } }{2*(-16)}[/tex]  Expresion (A)

and

[tex]\frac{-54-\sqrt{54^{2}-4*(-16)*40 } }{2*(-16)}[/tex] Expresion (B)

Solving the Expresion (A):

[tex]\frac{-54+\sqrt{5476 } }{2*(-16)}= \frac{-54+74}{2*(-16)}=\frac{20}{2*(-16)}=\frac{20}{-32}= -\frac{5}{8}[/tex]

Solving the Expresion (B):

[tex]\frac{-54-\sqrt{5476 } }{2*(-16)}= \frac{-54-74}{2*(-16)}=\frac{-128}{2*(-16)}=\frac{-128}{-32}= 4[/tex]

These results indicate the time it will take for the object to hit the ground can be -5/8 and 4. Since the time cannot be negative, then the time it will take for the object to hit the ground will be 4.

Answer:

4 seconds

Explanation:

i checked on the test and the other person was right give them brainliest

Answer:

Package's vertical displacement(s) = 22.12 meter

Explanation:

Given:

Speed of plane = 120 m/s

Total distance = 255 m

Find:

Package's vertical displacement(s)

Computation:

Time taken = Distance / Speed

Time taken = Total distance / Speed of plane

Time taken = 255 / 120

Time taken = 2.125 s

Acceleration due to gravity(g) = 9.8 m/s²

Initial velocity (u) = 0

So,

Package's vertical displacement(s) = ut + (1/2)gt²

Package's vertical displacement(s) = (0)(2.125) + (1/2)(9.8)(2.125)²

Package's vertical displacement(s) = 22.12 meter

Answer: -22.1

Explanation:

I just did the Khan Academy and that was the answer, not the one provided by that one person. :)))

That's called "lightning".

Answer:

The lightning itself is the transfer of charge from one region of a cloud to another or between the cloud and Earth. The narrow channel within which the flash of lightning occurs is heated suddenly to ~ 30,000 K, with essentially no time to expand.

Explanation:

Hope it helps

Answer:

v_squid = - 2,286 m / s

Explanation:

This exercise can be solved using conservation of the moment, the system is made up of the squid plus the water inside, therefore the force to expel the water is an internal force and the moment is conserved.

Initial moment. Before expelling the water

          p₀ = 0

the squid is at rest

Final moment. After expelling the water

         [tex]p_{f}[/tex] = M V_squid + m v_water

         p₀ = p_{f}

          0 = M V_squid + m v_water

           c_squid = -m v_water / M

The mass of the squid without water is

            M = 9 -2 = 7 kg

let's calculate

           v_squid = 2 8/7

           v_squid = - 2,286 m / s

The negative sign indicates that the squid is moving in the opposite direction of the water

Answer:

[tex]\omega_2=0.891\ rev/s[/tex]

Explanation:

Given that

Radius , r= 3.03 m

Mass of disk , M= 145 kg

Initial angular velocity

ω=0.681 rev/s

Mass of person , m= 65.4 kg

Velocity of person , V= 3.41 m/s

Initial mass moment of inertia

[tex]I_1= \dfrac{M\times R^2}{2}[/tex]

[tex]I_1= \dfrac{145\times 3.03^2}{2}=665.61\ kg.m^2[/tex]

Final mass moment of inertia

[tex]I_2= \dfrac{M\times R^2}{2}+m\times R^2[/tex]

[tex]I_2= \dfrac{145\times 3.03^2}{2}+65.4\times 3.03^2=1266.04\ kg.m^2[/tex]

[tex]Final\ angular\ velocity =\omega_2[/tex]

By using angular momentum equation

[tex]I_1\times \omega+m\times V\times R=I_2\times \omega_2[/tex]

[tex]665.61\times 0.681+65.4\times 3.41\times 3.03=1266.04\times \omega_2[/tex]

[tex]1129.01= 1266.04\times \omega_2[/tex]

[tex]\omega_2=\dfrac{1129.01}{1266.04}[/tex]

[tex]\omega_2=0.891\ rev/s[/tex]

Thus the angular velocity will be 0.891 rev/s

Answer:

V = 268.8 m/s

Explanation:

The speed of a wave in general is given by the following formula:

V = fλ

where,

V = Speed of that wave

f = Frequency of the wave

λ = wavelength of the wave

In this case we have a sound wave, travelling across carbon dioxide. The properties of sound wave are as follows:

V = Speed of Sound in Carbon dioxide = ?

f = frequency of sound wave = 140 Hz

λ = wavelength of sound wave = 1.92 m

Therefore,

V = (140 Hz)(1.92 m)

V = 268.8 m/s

Answer:

Work input W = -200.39 KJ

Explanation:

From the question, we are given;

m = 1.15 kg

Constant temperature T1 = T2 = 27 + 273 = 300k

Since the temperature is constant, we can say that the process is isothermal

P1 = 111 KPa

P2 = 0.84 MPa = 0.84 * 1000 KPa = 840 KPa

Now what we want to calculate is W1-2

Mathematically, for isothermal process;

W1-2 = mRTlnP1/P2

where R can be obtained from table and it is equal to 0.287 KJ/kg.k

Hence;

W1-2 = (1.15)(0.287)(300)(ln 111/840)

W1-2 = 99.015 * -2.023871690525 = -200.39 KJ

Kindly note that the value of the work is negative because work is done on the system and not by the system

Explanation:

Given:

distance between two sphere =0.35 m

Electrical repel force =0.035 N

Electrical repel force after connecting wire =0.055 N.

The electrical force between the two spheres:

[tex]F=k \frac{q_{1} q_{2}}{r^{2}}[/tex]

The electrical force between the two spheres after the wire is attached and removed:

[tex]F=k \frac{q^{2}}{r^{2}}[/tex]

[tex]q^{2}=\frac{F r^{2}}{k}[/tex]

[tex]q=r \sqrt{\frac{F}{k}}=0.35 \times \sqrt{\frac{0.055}{8.99 \times 10^{9}}}=6.46 \times 10^{-7} \mathrm{C}[/tex]

So the total charge of the two spheres [tex]=2 q=2 \times 6.46 \times 10^{-7}=1.29 \times 10^{-6} \mathrm{C}[/tex]

Then before connecting the wire, one sphere charge was [tex]q[tex] and the charge of the other sphere was [tex]\left(1.29 \times 10^{-6}-q\right)[/tex]

The electrical force between the two spheres before connecting the wire:

[tex]F=k \frac{q\left(1.29 \times 10^{-6}-q\right)}{r^{2}}[/tex]

[tex]q\left(1.29 \times 10^{-6}-q\right)=\frac{F r^{2}}{k}=\frac{0.035 \times(0.35)^{2}}{8.99 \times 10^{9}}=0.348 \times 10^{-12}[/tex]

[tex]-q^{2}+\left(1.29 \times 10^{-6}\right) q-\left(0.348 \times 10^{-12}\right)=0[/tex]

[tex]-q^{2}+\left(1.29 \times 10^{-6}\right) q-\left(0.348 \times 10^{-12}\right)=0[/tex]

Answer:

The material will still remain afloat.

Explanation:

The fact that the material floated on water as a solid piece means that the material is less dense than water. When a material is less dense than another liquid material, the material floats in the denser material. Cutting holes in the material will not reduce the buoyancy of the material. If the material had not floated as a single solid piece, then it will be said to be denser than the liquid material, and in such a case, if a strategic hole is cut on it to reduce its weight while maintaining its immediate volume, then it can be made to float. This is the principle behind metal floating ships.

Answer:

(a) Error: Other's ; Correction: Others'

(b) Error: to ; Correction: for

(c) Error: with ; Correction: of

(d) Error: prepares ; Correction: prepare

Explanation:

a)  The error is in the word "other's" as the position of apostrophe is wrong, so the correct word will be "others'", it shows plural nouns.

b)  The error is in the word "to", so the correct word will be "for" as for is use to talk about a purpose.

c)  The error is in the word "with"  and the correct word will be "of" as of indicates relationships between other words including things that made of other things.

d)  The error is in the word "preapres" and the correct word will be "prepare".

Answer:

Yes great job it was well written!:)

Answer:

Explanation:

Magnetic field = permeability x turn density x current

Magnetic field = 0.22T

turn density = 4150 /1.6 = 2593.75 t/m

permeability : µ = k µ°

µ°= 4 π 10^-7

k = 1

I = 0.22 / 4 π 10^-7 * 2593.75 = 0.22 10^7 /32594 = 67.497 A

Answer:

This statement is not true

Explanation:

Because The normal magnetic field line points out from the north magnetic pole and in from the south magnetic pole.

Answer:

false

Explanation:

hope this helps :)

Answer:

c) A series of RC circuits.

Answer:

a) tangent ; b) 153.88 yds ; c) No , less than or equal to 45° ; D) 45°

Explanation:

Given the following ;

From the triangle sketch :

Base length = 50 yards

Angle of elevation = 72°

a. Which trigonometric ratio would you use to calculate how high the blimp will be above the 50 yard line?

Using trigonometry :

The height of the blimp will be calculated using :

Tangent :

Tan θ = opposite / Adjacent

B.) How high above the ground is the blimp?

Using :

Tan θ = opposite / Adjacent

Θ = 72° ; adjacent = 52, opposite = height(h)

Tan 72° = h / 50

h = 3.0776835 * 50

h = 153.88 yds

C.) In order to be able to read the advertisement on the side of the blimp the highest the blimp can be is 150 feet. Will the fans be able to read the advertisement?

1 yard = 3 Feets

153.88 yards = 3 * 153.88

= 461.65 feets

No, because the height of the blimp is 461.65 Feets which is greater than 150 Feets.

To make viewing possible, the angle of elevation should be:

50 yards is equivalent to (3 * 50) = 150 feets

Max imum Height of blimp = 150 Feets

From pythagoras ;

Tanθ = 150 Feets / 150 Feets

Tanθ = 1

θ = tan^-1(1)

θ = 45°

To make viewing advertisement possible, angle of elevation should not exceed 45°

d.)If height of blimp is 150 Feets, then the exact angle of elevation will be 45°

Answer:

A car driving in a straight line 20 m/s

Explanation:

ayepecks silly

Answer:

1.2 kg m²

Explanation:

Angular momentum is conserved:

L = L

Iω = Iω

(4.6 kg m²) (1.0 rev / 1.5 s) = I (2.5 rev/s)

I = 1.2 kg m²

Answer:

Explanation:

Let the angle required be θ with direction opposite to current .

cos θ = 3 / 5

θ = 53° .

Resultant velocity towards the opposite side

= √ ( 5 ² - 3²)

= 4 km /h

distance covered = 1.2 km

time taken = 1.2 / 4 = .3 h

= 18 min .

Answer:

False

Explanation:

Total internal reflection is a condition that occurs when light travels from dense medium to less dense medium.

From the table given in the question above,

Refractive Index of Whale oil = 1.460

Refractive Index of vacuum = 1

From the above, we can see that the whale oil has a higher Refractive Index than vacuum. This implies that the whale oil is denser than the vacuum.

Therefore, total internal reflection will occur when light travels from whale oil to vacuum because the whale oil is denser than the vacuum.

Answer: hello i am a hacker

Explanation:

magnesium sulphate=(24*1)+(32*1)+(16*4)=120                                                             water=H2O=(1*2)+(1*16)=18                                                                                                        carbon dioxide=CO2=(12*1)+(16*2)=44                                                                                     ammonia=NH3=(14*1)+(1*3)=17                                                                                                   alminiumsulphate=AL2(SO4)3=(26*2)+(32*3)+(12*16)=340                                                          hydrogen peroxide=H2O2=(1*2)+(16*2)=34                                                              zinc sulphate=ZNSO4=(65*1)+(32*1)+(16*4)=161

Answer:

0.477 Hz

2.09 s

Explanation:

y = A sin(ωx − φ)

A is the amplitude, ω is the angular frequency, and φ is the phase shift.

ω = 3 rad/s

f = ω / 2π ≈ 0.477 Hz

T = 1/f ≈ 2.09 s

Answer:

Work done by charge (W) = 0.050 (Approx)

Explanation:

Given:

Charge (q) = 0.0042 C

Potential difference(V) = 12.0 V

Find:

Work done by charge

Computation:

Work done(W) = qV

Work done by charge (W) = (0.0042)(12)

Work done by charge (W) = 0.0504

Work done by charge (W) = 0.050 (Approx)

Answer:

Work done by charge (W) = 0.050 (Approx)

Explanation:

Charge (q) = 0.0042 C

Potential difference(V) = 12.0 V

Find:

Work done by charge

Computation:

Work done(W) = qV

Work done by charge (W) = (0.0042)(12)

Work done by charge (W) = 0.0504

Work done by charge (W) = 0.050 (Approx)

Answer:

37.8 m

Explanation:

At point 0, the ball is at height y₀.

At point 1, the ball is at height 30 m.

At point 2, the ball is at height 0 m.

Given:

y₁ = 30 m

y₂ = 0 m

v₀ = 0 m/s

a = -10 m/s²

t₂ − t₁ = 1.5 s

Find: y₀

Use constant acceleration equation.

y = y₀ + v₀ t + ½ at²

Evaluate at point 1.

y₁ = y₀ + v₀ t₁ + ½ at₁²

30 m = y₀ + (0 m/s) t₁ + ½ (-10 m/s²) t₁²

30 = y₀ − 5t₁²

Evaluate at point 2.

y₂ = y₀ + v₀ t₂ + ½ at₂²

0 m = y₀ + (0 m/s) t₂ + ½ (-10 m/s²) t₂²

0 = y₀ − 5t₂²

y₀ = 5t₂²

Substitute:

y₀ = 5 (1.5 + t₁)²

y₀ = 5 (2.25 + 3t₁ + t₁²)

y₀ = 11.25 + 15t₁ + 5t₁²

30 = 11.25 + 15t₁ + 5t₁² − 5t₁²

30 = 11.25 + 15t₁

t₁ = 1.25

30 = y₀ − 5t₁²

30 = y₀ − 5(1.25)²

y₀ ≈ 37.8

Answer: A. The forces on an object in motion are balanced.

Explanation:

The dynamic equilibrium is defined as the phase when an object moves at a constant velocity such that all forces on the object are balanced.

Simple case of dynamic equilibrium: A horizontal force is applied to an object making it run with a constant velocity across a surface.

Hence, the statement describes dynamic equilibrium is " The forces on an object in motion are balanced. "

So, the correct option is "A".

Answer:

Hope this helps!

Answer: 43.2 J

Explanation:

Work = change in KE

initial KE = 0

final KE = 1/2mv^2 = 1/2(0.370 kg)(15.2778 m/s)^2 = 43.2 J

i'm not sure about sig figs though