Easy question just don’t understand it please help.

Answer:

[tex]4.47\ \text{km/h}[/tex]

Explanation:

[tex]\dfrac{da}{dt}[/tex] = Rate at which the distance between A and starting point of B is changing = -20 km/h

[tex]\dfrac{db}{dt}[/tex] = Rate at which the distance of B is changing = 15 km/h

[tex]\dfrac{dc}{dt}[/tex] = Rate at which the distance between A and B is changing

Time after which the rate at which the distance between A and B is changing is 4 hours

Distance covered by A in 4 hours = [tex]20\times 4=80\ \text{km}[/tex]

a = Distance remaining to the start point of B = [tex]110-80=30\ \text{km}[/tex]

b = Distance covered by B in 4 hours = [tex]15\times 4=60\ \text{km}[/tex]

Distance between A and B after 4 hours

[tex]c=\sqrt{a^2+b^2}\\\Rightarrow c=\sqrt{30^2+60^2}\\\Rightarrow c=67.08\ \text{km}[/tex]

[tex]c^2=a^2+b^2[/tex]

Differentiating with respect to time we get

[tex]c\dfrac{dc}{dt}=a\dfrac{da}{dt}+b\dfrac{db}{dt}\\\Rightarrow \dfrac{dc}{dt}=\dfrac{a\dfrac{da}{dt}+b\dfrac{db}{dt}}{c}\\\Rightarrow \dfrac{dc}{dt}=\dfrac{30\times -20+60\times 15}{67.08}\\\Rightarrow \dfrac{dc}{dt}=4.47\ \text{km/h}[/tex]

The rate at which the distance between the ships is changing at 4 PM is [tex]4.47\ \text{km/h}[/tex].

Answer:

 u = 14 m / s

Explanation:

For this exercise let's use conservation of energy

starting point. On the floor just when u speeding out

         Em₀ = K = ½ m v²

final point. When on top of the building, no speed

         Em_f = U = m g h

energy is conserved

          Em₀ = Em_f

          ½ m v² = m g h

          v = u

          u = [tex]\sqrt{2 g h}[/tex]

          u=  [tex]\sqrt{2 \ 9.8 \ 10}[/tex]

          u = 14 m / s

Answer:

If light enters any substance with a higher refractive index (such as from air into glass) it slows down. The light bends towards the normal line. If light travels enters into a substance with a lower refractive index (such as from water into air) it speeds up. The light bends away from the normal line.

Answer:

3. (a) - is the answer most likely

4: (a)

5 (d or c)

6 (b)

Answer:

6.26 m/s

Explanation:

Since we are neglecting viscous losses and surface tension effects in the liquid jet, by conservation of energy, the potential energy loss of the jet = kinetic energy gain of the jet

So, mgh = 1/2mv² where m = mass of water in jet, g = acceleration due to gravity = 9.8 m/s², h = height of outlet = 2.0 mand v = velocity of liquid jet

So, mgh = 1/2mv²

gh = 1/2v²

v² = 2gh

v = √(2gh)

v = √(2 × 9.8 m/s² × 2.0 m)

v = √(39.2 m²/s²)

v = 6.26 m/s

Answer:

The example of the center of the gravity is the middle of a seesaw

Explanation:

I hope this will help you and plz mark me brainlist

the exosphere is the least dense

Answer:

exosphere

Explanation: Just took the quiz and got an A, 100%

Answer:

Energy in carriage (Potential energy) = 4,116 J

Explanation:

Given:

Mass of baby = 20 kg

Height = 21 m

Find:

Energy in carriage (Potential energy)

Computation:

The energy accumulated in an object as a result of its location relative to a neutral level is known as potential energy.

In carriage accumulated energy is potential energy.

Energy in carriage (Potential energy) = mgh

Energy in carriage (Potential energy) = (20)(9.8)(21)

Energy in carriage (Potential energy) = 4,116 J

Answer:

r₂ = 0.316 m

Explanation:

The sound level is expressed in decibels, therefore let's find the intensity for the new location

            β = 10 log [tex]\frac{I}{I_o}[/tex]

let's write this expression for our case

           β₁ = 10 log \frac{I_1}{I_o}

           β₂ = 10 log \frac{I_2}{I_o}

          β₂ -β₁ = 10 ( [tex]log \frac{I_2}{I_o} - log \frac{I_1}{I_o}[/tex])

          β₂ - β₁ = 10 [tex]log \frac{I_2}{I_1}[/tex]

          log \frac{I_2}{I_1} = [tex]\frac{60 - 20}{10}[/tex] = 3

           [tex]\frac{I_2}{I_1}[/tex] = 10³

           I₂ = 10³ I₁

having the relationship between the intensities, we can use the definition of intensity which is the power per unit area

           I = P / A

           P = I A

the area is of a sphere

          A = 4π r²

the power of the sound does not change, so we can write it for the two points

          P =  I₁ A₁ =  I₂ A₂

          I₁ r₁² = I₂ r₂²

we substitute the ratio of intensities

          I₁ r₁² = (10³ I₁ ) r₂²

         r₁² = 10³ r₂²

         r₂ = r₁ / √10³

we calculate

          r₂ = [tex]\frac{10.0}{\sqrt{10^3} }[/tex]

          r₂ = 0.316 m

Answer:

Renewable energy minimizes carbon pollution and has a much lower impact on our environment. And it's having its moment in the sun. "Giving more New Yorkers access to renewable energy can allow them to reduce their own energy bills while reducing stress on the grid and demand for fossil fuel power.

The force acting on the object is constant, so the acceleration of the object is also constant. By definition of average acceleration, this acceleration was

a = ∆v / ∆t = (6 m/s - 0) / (1.7 s) ≈ 3.52941 m/s²

By Newton's second law, the magnitude of the force F is proportional to the acceleration a according to

F = m a

where m is the object's mass. Solving for m gives

m = F / a = (10 N) / (3.52941 m/s²) ≈ 2.8 kg

Answer:

The induced current can be increased in the coil in the following ways: By increasing the strength of the magnet. By increasing the speed of the magnet through the coil.

Explanation:

Answer:

the net work done on the object is 80 J.

Explanation:

Given;

force applied on the object, F = 100 N

mass of the object, m = 20 kg

speed of the object, v = 0.2 m/s

distance moved by the object, d = 0.8 m

The net work done on the object is calculated as follows;

W = F x d

W = 100 N x 0.8 m

W = 80 J

Therefore, the net work done on the object is 80 J.

Answer:

The force will be "9.8 N".

Explanation:

The given values are:

mass,

m = 0.7 kg

M = 2

g = 9.8

Now,

⇒  [tex]\tau = T \alpha[/tex]

then,

⇒  [tex]\frac{1}{2}mR^2(\frac{1}{R}\frac{dv}{dt}) =M(g-a_t)R[/tex]

⇒  [tex]\frac{1}{2}m \ a_t=m(g-a_t)[/tex]

⇒  [tex]a_t=\frac{2g}{(\frac{m}{M} +2)}[/tex]

On substituting the values, we get

⇒      [tex]=\frac{2\times 9.8}{\frac{0.7}{2} +2}[/tex]

⇒      [tex]=8.34 \ m/s[/tex]

hence,

⇒  [tex]T=mg+M(g-a_t)[/tex]

On substituting the values, we get

⇒      [tex]=0.7\times 9.8+2(9.8-8.34)[/tex]

⇒      [tex]=6.86+2(1.46)[/tex]

⇒      [tex]=6.86+2.92[/tex]

⇒      [tex]=9.8 \ N[/tex]

Answer:

air pressure

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Answer:

Cow

Explanation:

Hr is a great place to work for

Answer:

cow

Explanation:

donation of seed to various agro section

Answer:

1) It seems that he would need the central gravitational force

   (the sun)

2) Also the planets would need to be included (orbits around the sun)

    Mercury, Venus, Earth, Mars, Jupiter, Saturn, etc.

3. Then, many of the planets have significant objects (moons) rotating about them.

Those would seem to be objects to be included in a model of the solar system.

1) He would need the central gravitational force (the sun)

2) The planets would need to be included: Mercury, Venus, Earth, Mars, Jupiter, Saturn, etc.

3) Many of the planets have specific moons rotating about them.

Larry should put the Earth between the planets Venus, and Mars.

Answer:

A person that consistently runs 3 meters evert second

Explanation:

Because as a human walks 3 meters every 1 second it isn't consider uniform. It has to be in a erect motion

Answer:

3.54

Explanation:

some nerd thing I found it on Yahoo answers

Answer:

3.54º

Explanation:

Find the blue θ first

sin⁻¹(540x10⁻⁹/2.88x10⁻⁶)=8.99°

Then find the orange θ

sin⁻¹(625x10⁻⁹/2.88x10⁻⁶)=12.53°

Take the differences and subtract

12.53°－8.99°=3.54°

Answer:

So the answer to the question "who invented table tennis?" is ... Englishman David Foster. An English Patent (number 11,037) was filed on 15 July 1890 when David Foster of England introduced the first action game of tennis on a table in 1890. Only one example is known to have survived and it's now on display in the ITTF Museum.

Explanation:

Answer:

The third approach to cross-cultural studies of personality is the combined approach, which serves as a bridge between Western and indigenous psychology as a way of understanding both universal and cultural variations in personality

Explanation:

Answer:

The third approach to cross-cultural studies of personality is the combined approach, which serves as a bridge between Western and indigenous psychology as a way of understanding both universal and cultural variations in personality

Answer:

como  ías

Explanation:

Answer:

V = 0.0723 volts = 72.3 milivolts

Explanation:

The emf induced in the rod is the motional emf due to the magnetic field. This motional emf can be calculated by the following formula:

[tex]EMF = V = vBl Sin\theta[/tex]

where,

V = Motional EMF = ?

v = speed of rod = 12.5 m/s

B = Magnetic Field = 6.23 mT = 0.00623 T

l = Length of rod = 92.9 cm = 0.929 m

θ = angle between v and B = 90°

Therefore,

[tex]V = (12.5\ m/s)(0.00623\ T)(0.929\ m)Sin\ 90^o\\[/tex]

V = 0.0723 volts = 72.3 milivolts

The distance the block-bullet compress the spring is 0.36 m.

The final velocity of the bullet- block system is calculated as follows;

[tex]m_1 u_1 + m_2 u_2 = v(m_1 + m_2)\\\\0.034(120) + 1.24(0) = v(0.034+ 1.24)\\\\4.08 = 1.274v\\\\v = \frac{4.08}{1.274} \\\\v = 3.2 \ m/s[/tex]

The compression of the spring is calculated by applying principle of conservation of energy;

[tex]\frac{1}{2} kx^2 = \frac{1}{2} mv^2\\\\kx^2 = mv^2\\\\x^2 = \frac{mv^2}{k} \\\\x = \sqrt{\frac{mv^2}{k} } \\\\x = \sqrt{\frac{(1.274 \times 3.2^2)}{99} }\\\\x = 0.36 \ m[/tex]

Thus, the distance the block-bullet compress the spring is 0.36 m.

Learn more about conservation of energy here: https://brainly.com/question/166559

Answer:

speed: 35m/s

direction: left

Explanation:

Assuming the right side is the positive direction:

before explosion:

P = mv = 0

after explosion:

P' = 15P + 5P

(Set the velocity of the 15kg piece after explosion as v1' and the velocity of the 5kg piece after explosion as v2')

P' = 0.75mv1' + 0.25mv2'

P' = (15kg)v' + (5kg)(105m/s)

P' = 525kg/m/s + (15kg)v1'

P = P'

525kg/m/s + (15kg)v1' = 0

(15kg)v1' = -525kg/m/s

v1' = -35m/s

speed = |-35| = 35m/s

direction is to the left since the right side is the positive direction.

Answer:

66.67 km/h

Explanation:

20 + 30 = 50

50/.75 = 66.67