I need help with this review question.

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:

It cannot be constant because if it does not change and each time it increases its strength and speed.

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

Answer:

the answers the correct one is A

Explanation:

Let's analyze the situation, the expression for ideal gases is

         PV = n R T

in this case n is the number of moles of the gas remains constant, so we see that there is a relationship between volume, pressure and temperature.

For the experiment we are conducting we must ensure that the temperature remains constant, one way to achieve this is by placing a small thermometer on the surface of the cylinder.

By rapidly compressing part of the work done, it is converted into internal energy of the gas molecules, and from there it is transformed into its temperature. One way to reduce this effect is to COMPRESS SLOWLY and thus keep the temperature constant.

This method of allowing to check

          P V = cte

when checking the answers the correct one is A

Answer:

the pressure the balloon exerts on the table is 1,730.77 N/m²

Explanation:

Given;

weight of the water balloon, F = 4.5 N

area of the balloon, A = 2.6 x 10⁻³ m²

The pressure the balloon exerts on the table is calculated as follows;

[tex]P = \frac{F}{A}[/tex]

substitute the given values and solve for pressure, P;

[tex]P = \frac{4.5}{2.6 \times 10^{-3}} \\\\P = 1,730.77 \ N/m^2[/tex]

Therefore, the pressure the balloon exerts on the table is 1,730.77 N/m²

Answer:

Get to work.

Explanation:

This is not Brainly material. This is a project that you need to get started on and do your best on. It always looks worst before you get started on it. Just sink your teeth in and you'll be finishing it up before you know it.

Answer:

careers related to the promotion or treatment of reproductive health and choose one career to focus on. You are going to identify the key factors of the educational path that you would need to take to work in this career, the annual salary that you would earn, the schedule that you may find yourself working, physical requirements for the job, and how long it will take you to achieve this goal.

Explanation:

Answer:

  k y -b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]

give us some initial conditions

1) friction force fr = 1N when v = 4m / s

2) an initial displacement of x = 0.08 m for t=0 s

Explanation:

In this exercise, you are asked to state the problem you are posing. We are going to find the equation of motion for this exercise. Let's start with Newton's second law

Let's set a reference system with the y-axis in a vertical and positive direction upwards.

We have four forces: an external downward force, negative in sign, the but that goes down and is negative, the Hook force that goes up and is positive and the friction force that opposes the movement, in this case it goes down being negative

let's write Newton's second law

          F_e -F -fr - W = m a

where

          F_e = -kDy = - k y

          fr = - b v = -b dy / dt

          W = mg

we substitute for the specific case, that is, using the signs

          k y  -b [tex]\frac{dy}{dt}[/tex] - m g - F = m [tex]\frac{d^2y}{dt^2}[/tex]

In the initial condition of the problem, before starting the movement, the friction force is zero and the acceleration is also zero

         k y - m g - F = 0

from this equation you can find the spring constant, y= 9m and F=2 N

It is not clear if when the movement starts this external force becomes zero, but since it balances the weight we can eliminate the two forces that have the same magnitude and opposite direction, so the equation remains

              k y - b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]

give us some initial conditions

1) friction force fr = 1N when v = 4m / s

2) an initial displacement of x = 0.08 m for t=0 s

therefore, to initiate the movement, a small external force F 'is applied that moves the system to a new equilibrium position and this small force F' is made zero, thus initiating an oscillatory movement, described by the equation.

             k y -b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]

This is a differential equation of the second degree, therefore it needs two initial conditions for its complete solution

The initial amount of displacement corresponds to the amplitude of movement A = 0.08 m

Answer:

When the glass rod is rubbed with silk, the silk strips electrons from the rod, leaving it a positive charge. When the hard rubber rod is rubbed with wool, it gains electrons from the wool, gaining a negative charge.

Explanation:

In the CrystPX Technology process, suspension crystallization of paraxylene (PX) in the xylene isomer mixture is used to produce paraxylene crystals.  At the back end of the process, high paraxylene recovery is obtained by operating the crystallizers at colder temperatures.

Paraxylene crystals are created using the CrystPX Technology by suspending paraxylene (PX) in a mixture of xylene isomers. High paraxylene recovery is achieved at the end of the process by running the crystallizers at lower temperatures.

The paraxylene technology from BP, a novel method using single stage crystallization for paraxylene (pX) recovery, is licensed exclusively to Lummus Technology for use around the world.

This cutting-edge architecture makes the Lummus Technology/BP pX crystallization technology the most energy-efficient paraxylene recovery process, together with excellent feed impurity tolerance and low total unit fuel consumption.

The Lummus Technology/BP paraxylene process has a high degree of dependability, is inexpensive, and can take a variety of feed compositions.

Therefore, With the aid of isomerization over a non-noble metal catalyst, the yield of xylene is improved even further. Optimized fractionation lowers reboiler duty, resulting in less energy use and emissions.

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Answer:

I believe it is true, but our brains don’t do it, I think it is the lenses in our eyes that do it. I might be wrong tho

Explanation:

Answer:

Yes it is true that our eyes form upside-down images, which are flipped right-side-up by our brain.

Answer:

I don't know how to do it the subject

The centripetal acceleration of the car when there is the radius and the speed is given so it should be considered as the option b. 36 [tex]m/s^2[/tex].

Since

The radius is 25 cm and the speed should be 30 m/s

Now the following formula should be used

Acceleration = speed^2/ radius

= 30^2 / 25

= 900 / 25

= 36 [tex]m/s^2[/tex]

Therefore, The centripetal acceleration of the car should be considered as the option b. 36 [tex]m/s^2[/tex].

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Answer:

[tex]\theta=76\ rad[/tex]

Explanation:

Hoven that,

Initial angular velocity of the wheel = 24 rad/s

Final angular velocity = 14 m/s

Time, t = 4 s

We need to find how many radians does the wheel turn through during the 4 s interval. Let the displacement is [tex]\theta[/tex]. Using second equation of rotational kinematics to find it such that,

[tex]\theta=\omega_i t+\dfrac{1}{2}\alpha t^2[/tex]

Where

[tex]\alpha[/tex] is angular acceleration

[tex]\alpha =\dfrac{\omega_f-\omega_i}{t}\\\\\alpha =\dfrac{14-24}{4}\\\\\alpha =-2.5\ rad/s^2[/tex]

So,

[tex]\theta=24\times 4+\dfrac{1}{2}\times (-2.5)\times 4^2\\\\\theta=76\ rad[/tex]

So, it will turn 76 radian during the 4 s interval.

Answer:

isopropyl alcohol would form smaller droplets, because it has lower surface tension than water has

Explanation:

Ap3x

The droplets made of isopropyl alcohol instead of water be smaller due to surface tension.

The single drop of a liquid in the form of sphere is called droplet.

Water can form large dewdrops in nature. Isopropyl alcohol would form smaller droplets, because it has lower surface tension than water.

Surface tension is the property of the liquid to acquire minimum surface area.

Thus, droplets made of isopropyl alcohol instead of water be smaller.

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Answer:

I'd say D

Explanation:

because not all weather happens within the atmosphere, and most weather depends on region (lile if your near the equator or not)

Answer:

v2(final)=5 m/s

Explanation:

we are going to use the conservation of momentum here

m1*v1(initial)+m2*v2(initial)=m1*v1(final)+m2v2(final)

m1=7 kg  v1(initial)=10 m/s

m2=14 kg  v2(initial)=0 m/s (bc initially it is at rest)

v1(final)= 0 m/s (m1 stops moving after the collision)

v2(final)=?

7*10+14*0=7*0+14*v2(final)

70=14v2(final)

v2(final)=70/14 m/s=5 m/s

Answer:

 P and S waves slow down when they reach this layer. The asthenosphere, also known as the magma chamber, is the uppermost component of the mantle. This layer is partially molten and is a ductile zone in a tectonically poor state.

It's almost hard and seismic waves move through the asthenosphere at a slow rate. The fragile lithosphere and the uppermost portion of the asthenosphere are assumed to be rigid.

seismic waves travel more quickly through denser materials and therefore generally travel more quickly with the depth it moves more slowly through a liquid than a solid. Molten areas within the Earth slow down P waves and stop S waves because their shearing motion cannot be transmitted through a liquid. Partially molten areas may slow down the P waves and attenuate or weaken S waves.

hope this helps...

S and P wave slow down and stop in  the uppermost part of the mantle. - For this, scientists have concluded that the uppermost part of the mantle is partially-molten.

A planetary body's mantle is a layer that is surrounded by the crust on top and the core underneath. The largest and most substantial layer of a planetary body, mantles are often comprised of rock or ice. Planetary bodies that have undergone density differentiation typically have mantles. Mantles are found on all terrestrial planets (including Earth), many asteroids, and a few planetary moons.

Between the crust and the outer core, there is a silicate rock layer known as the Earth's mantle. Despite being mostly solid, it behaves like a viscous fluid over geological time. Oceanic crust is created by the partial melting of the mantle at mid-ocean ridges, and continental crust is created by the partial melting of the mantle at subduction zones.

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Answer:

B. it increases

Explanation:

As shown in the table provided, the speed of sound in water (1493 m/s) is greater than the speed of sound in air (346 m/s).

Answer:

B is the correct answer.

Explanation:

Answer:

B

Explanation:

Explanation:

As pressure increases, with temperature constant, density increases. Conversely when temperature increases, with pressure constant, density decreases. Air density will decrease by about 1% for a decrease of 10 hPa in pressure or 3 °C increase in temperature.

Answer: The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. ... The force created by the electric field is much stronger than the force created by the magnetic field.

Explanation: An electric field is an invisible force field created by the attraction and repulsion of electrical charges (the cause of electric flow), and is measured in Volts per meter (V/m).

Answer:

The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field.  The force created by the electric field is much stronger than the force created by the magnetic field.

Explanation:

Ggl

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 average speed throughout the journey was 76.36 kilometers per hour.

Explanation:

Given that a car driver spends 3hrs driving at an average speed of 80km / hr, stops for 30 minutes to have some rest, and then drives at an average speed of 90km / hr for 2 hours, to determine the average speed during the whole journey the following calculation must be performed:

80 km / h x 3 = 240 km

90 km / h x 2 = 180 km

240 + 180 = 420 km

3 + 2 + 0.5 = 5.5 hours

420 / 5.5 = 76.36

Thus, the average speed throughout the journey was 76.36 kilometers per hour.

Answer:

Newton's first law of motion concerns any object that has no force applied to it.

Explanation:

three laws of motion and the law of universal gravitation.

Answer:18 watts

Explanation:i just got this question trust me

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Answer:

The speed of the bird is 1.00% of the speed of sound.

Explanation:

The speed of the bird can be found by using the Doppler equation:

[tex] f = f_{0}(\frac{v - v_{r}}{v - v_{s}}) [/tex]

Where:

v: is the speed of sound = 343 m/s

f₀: is the frequency emitted = 1490 Hz

f: is the frequency observed = 1505 Hz

[tex]v_{r}[/tex]: is the speed of the receiver = 0 (it is stationary)

[tex]v_{s}[/tex]: is the speed of the source =?

The minus sign of [tex]v_{s}[/tex] is because the source is moving towards the receiver.

By solving the above equation for [tex]v_{s}[/tex] we have:

[tex] v_{s} = v - \frac{f_{0}*v}{f} = 343 - \frac{1490*343}{1505} = 3.42 m/s [/tex]

The above speed in terms of the speed of sound is:

[tex]\% v_{s} = \frac{3.42}{343}\times 100 = 1.00 \%[/tex]

Therefore, the speed of the bird is 1.00% of the speed of sound.  

I hope it helps you!

Chris used a non-plane mirror to check out a box resting on a shelf, the focal length of the mirror is mathematically given as

f=8.38cm

Question Parameter(s):

The image of the box was located 15 cm behind the mirror

and the box was placed 19 cm from the mirror.

Generally, the equation for the focal length is mathematically given as

1/f=1/u+1/v

Therefore

1/f=1/15+1/19

f=8.3823529cm

In conclusion,  the focal length of the mirror

f=8.3823529cm

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Answer: 5 km per hour

Explanation:

if in 10 km there is 2 hours, then 10 divided by 2 is 5.