Emily sees a ship traveling at a constant speed along a straight section of a river. She walks parallel to the riverbank at a uniform rate faster than the ship. She counts equal steps walking from the back of the ship to the front. Walking in the opposite direction, she counts steps of the same size from the front of the ship to the back. In terms of Emily's equal steps, what is the length of the ship

Answer:Acceleration - time graph for a particle moving in a straight line is as shown in figure. Change in velocity of the particle from t = 0 to t = 6s is:-.

1 answer

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Top answer:

Change in velocity = (sum of area of graph) = ( 12 × 4 × 4 ) + ( 12 × ( + 2) ( - 1) ) - 4 = 8 - 4 = 4 x

Explanation:

Answer:

Let ω1 be the initial angular speed and ω2 the final angular speed:

α = (ω2- α1) / t      

corresponding to a = (v2 - v1) / t  

S (distance corresponds to theta)

1 rev = 2 pi      and 3.74 rev = 7.48 pi = 23.5 radians

S = 1/2 a t^2 linear     or S = 1/2 α t^2    angular acceleration

23.5 = 1/2 * 1.08 t^2     and t = 6.60 sec   for first 3.84 rev

b)  ω1 = 1.08 * 6.6 = 7.13 rad/sec    initial speed for second 3.74

23.5 = 7.13 t + .54 t^2        compare to S = v1 t + 1/2 a t^2

.54 t^2 + 7.13 t - 23.5 = 0    

t^2 + 13.2 t - 43.5 = 0

t = 2.7 sec for next 3.74

Check:

7.13 * 2.7 + .54 * 2.7^2 = 23.2 rad = 3.7 rad

From the relationship between acceleration a and g on an inclined plane, the angle of the slope is 13 degrees

Given that a solid sphere starts from rest and rolls down a slope that is 6.4 m long. The speed at the bottom of the slope is 5.3 m/s, the distance travelled is 6.4 m. That is,

Initial velocity U = 0 ( since it starts from rest)

Final velocity V = 5.3 m/s

distance S = 6.4 m

Let us first calculate its acceleration by using  third equation of motion.

[tex]V^{2}[/tex] = [tex]U^{2}[/tex] + 2aS

[tex]5.3^{2}[/tex] = 0 + 2 x 6.4a

28.09 = 12.8a

a = 28.09 / 12.8

a = 2.2 m / [tex]s^{2}[/tex]

To calculate the angle of the slope, let us use the relationship between acceleration a and g on an inclined plane.

acceleration a = gsin∅

substitute all the relevant parameters

2.2 = 9.8 sin∅

sin∅ = 2.2/9.8

sin∅ = 0.224

∅ = [tex]Sin^{-1}[/tex](0.224)

∅ = 12.97 degrees

∅ = 13 degrees (approximately)

Therefore, the angle of the slope is 13 degrees

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Answer:

Correct option is

C

The listener is moving towards the source of sound

The Doppler effect (or the Doppler shift) is the change in frequency or wavelength of a wave (or another periodic event) for an observer moving relative to its source.

So if both listener and source of sound are stationary or are moving with the same velocity that is relative velocity is zero, there won't be any change in frequency.

Thus, in this case, the effect will arise when a listener is moving towards the source of the sound.

Factors such as more crops, fewer predators, invasive species, and changes in the environment explain a decrease or increase in the birds and rodent populations.

Before 1997, both rodents and birds populations increased due to different factors. Moreover, these factors can be classified as natural or human-made factors. Here are the factors that mainly affected these animals:

Bird population:

Increase:

Decrease in predators that increase birds chances to survive (natural factor)

Increase in crops that improve food access for birds (human factor)

Decrease:

Invasive species or increase of predators (natural factor)

Destruction of natural habitats due to an increase in industry and extraction (human factor)

Rodent population:

Increase:

Decrease:

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Answer:

1

Explanation:

A=mgh=0.2*10*0.5=1 J

Answer:

Decline in soil health is a serious worldwide problem that decreases complexity and stability of agricultural ecosystems, commonly making them more prone to outbreaks of herbivorous insect pests. Potato (Solanum tuberosum L., Solanaceae) and onion (Allium cepa L., Amaryllidaceae) production is currently characterized by high soil disturbance and heavy reliance on synthetic inputs, including insecticides. Evidence suggests that adopting soil conservation techniques often (but not always) increases mortality and decreases reproductive output for the major insect pests of these important vegetable crops. Known mechanisms responsible for such an effect include increases in density and activity of natural enemy populations, enhanced plant defenses, and modified physical characteristics of respective agricultural habitats. However, most research efforts focused on mulches and organic soil amendments, with additional research needed on elucidating effects and their mechanisms for conservation tillage, cover crops, and arbuscular mycorrhizae.

Introduction

Soil erosion is a serious problem worldwide (Amundson et al., 2015). Although it is often overshadowed in public discourse by other concerns, such as climate change and invasive species, soil deterioration receives considerable attention from the scientific community (Montgomery, 2007; Borrelli et al., 2017; Berhe et al., 2018). In addition to the loss of agricultural productivity, soil erosion has been linked to increased emissions of greenhouse gases and reduced water quality (Amundson et al., 2015; Berhe et al., 2018). Global soil erosion is forecasted to increase in the near future because of cropland expansion, especially in the least economically developed areas (Borrelli et al., 2017).

As water cools the volume expands.

Answer: B. The volume of water will increase if cooled from 3°C to 2°C.

Machine translators:

Level of accuracy can be very low.

Accuracy is also very inconsistent across different languages.

Machines can't translate context.

Mistakes are sometimes costly.

Sometimes translation simply doesn't work.

Human translators:

Turnaround time is longer.

Translators rarely work for free.

Unless you use a translation agency, with access to thousands of translators, you're limited to the languages any one translator can work with.

Answer:

Ok thanks for the points though

Explanation:

Answer:

F-F(gr) = ma

a= {F-F(gr)}/m =

=(15-10)/15=0.33 m/s² (upward)

Answer:

0.25

Explanation:

That is the right answer.

The fraction of the initial kinetic energy is lost in the collision is 35.3%.

The given parameters:

The initial kinetic energy of the system collision is calculated as follows;

[tex]K.E_i = \frac{1}{2} mv_1_i^2 + \frac{1}{2} mv_2_i^2\\\\K.E_i = \frac{1}{2} (m)(8.3)^2 + \frac{1}{2} (m) (0)^2\\\\K.E_i = 34.445 m[/tex]

The final velocity of ball A after collision is calculated as follows;

[tex]u_1 + v_1 = u_2 + v_2\\\\8.3 + v_1 = 0 + 6.4\\\\v_1 = 6.4 - 8.3\\\\v_1 = -1.9 \ m/s[/tex]

The final kinetic energy of the system after collision is calculated as follows;

[tex]K.E_f = \frac{1}{2} m(-1.9)^2 + \frac{1}{2} m(6.4)^2\\\\K.E_f = 22.285 \ m \[/tex]

The fraction of the initial kinetic energy is lost in the collision is calculated as follows;

[tex]= \frac{K_i - K_f}{K_i} \\\\= \frac{34.445 - 22.285}{34.445} \\\\= 0.353\\\\= 35.3\%[/tex]

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The direct proportions rule allows to find the result for the energy produced by a solar cell is:

        E = 1,728 J

The efficiency of a solar cell is the percentage of incident energy that transforms into electricity.

The direct  proportions rule or three rule stable that if two quantities are proportional the product remains constant.

They indicate that the length of the solar cell is l = 12 cm = 0.12m. Let's find the area of ​​the solar cell.

        A = l²

        A = 0.12²

        A = 1.44 10⁻² m²

Let's use a direct proportion rule. If 1 m² receives 1000J of energy, how much does an area of ​​1.44 10⁻² m² receive?

        Energy_cell = 1000 J ( [tex]\frac{1.44 \ 10^{-2}}{1}[/tex] )

        Energy_ cell = 14.4 J

Let's use another direct ratio rule for efficiency.

       [tex]Energy_{produced} = Energy_{cell} \frac{12}{100} \\Energy_{produced} = 14.4 0.12 \\Energy_{produced} = 1.728 J[/tex]

In conclusion using the direct proportions rule we can find the result for the energy produced by a solar cell is:

        E = 1,728 J

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Answer:

3h/4

Explanation:

At speed v/2 height will be 3/4 h

Equation that describes the motion of point , bodies , and system of bodies without considering the force that cause them to move is called equation of motion in kinematics

When block is at top of first ramp

u=0 ( block was at rest )

a = g ( acceleration due to gravity

using equation of motion                                                                                                                                                                                                                                                                    

2as = v^2 - u^2

2gh = v^2

Then the block continued and reached a speed of v1 = v/2 on second ramp

now , final velocity = v= v1 =[tex]\sqrt{2gh}[/tex] / 2

u= [tex]\sqrt{2gh\\}[/tex]

s= h1

using equation of motion , we get

2as = v^2 - u^2

2(-g)h1 =( [tex]\sqrt{2gh}[/tex]/2)^2 - [tex]\sqrt{2gh}[/tex]

2(-g)h1 = (g h - 4 g h) / 2

h1 = 3/4 h

At speed v/2 height will be 3/4 h

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Answer:b

Explanation:

Answer:

The lobster let the claw go. so, B.

Explanation:

i hope this helps.

Answer:

Explanation:

Matter can be broken down into two categories: pure substances and mixtures. Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule.

Answer:

138

Explanation:

(since there's a blank next to "9x y j", I'm assuming the y of F(x, y) is 9x[tex]\sqrt{y}[/tex] j)

1) find the partial derivative of each:

[tex](6y^{\frac{3}{2} })i + (9x\sqrt{y} )j[/tex]  

 [tex]f_{x} =(6y^{\frac{3}{2} })_{x} = \int\limits{6y^{\frac{3}{2} }} \, dx = 6xy^{\frac{3}{2} } +c \\\\f_{y} = (9x\sqrt{y} )_{y} = \int\limits{9xy^{\frac{1}{2} } } \, dy = 9x(\frac{2}{3} )y^{\frac{3}{2} } +c = 6xy^{\frac{3}{2} } +c[/tex]

2) use partial integrals to make gradient of f:

take whatever you got from partial integral and add them together (if they repeat, just use it once)

[tex]F =[/tex] Vf (V = gradient of)

[tex]F(x, y) = 6xy^{\frac{3}{2} }[/tex]

3) Evaluate the integrals with given points:

Integral of F dotted with dr = F(point B) - F(point A) = F(3, 4) - F(1, 1)

[tex]F(point B) = 6(3)(4)^{\frac{3}{2} }\\F(Point A) = 6(1)(1)^{\frac{3}{2}}\\F(point B) - F(pointA) = 6(3)(4)^{\frac{3}{2} }-(6(1)(1)^{\frac{3}{2}})[/tex]

= 144 - 6 = 138 units of work

Work done by the force field F in moving an object from A to B = 138 J

Given data :

Force field F(x,y) = [tex]6y^{\frac{3}{2} }i + (9x\sqrt{y} ) j[/tex]  

Step 1 : determine the partial derivatives of the vector quantity

Fx = ∫ [tex]6y^{\frac{3}{2} }i = 6xy^{\frac{3}{2} } + c[/tex]

Fy = ∫ [tex](9x \sqrt{y})_{y} = 9x(\frac{2}{3})y^{\frac{3}{2} } + c[/tex]

Equating the partial derivatives :  

[tex]9x(\frac{2}{3})y^{\frac{3}{2} } + c[/tex]  = [tex]6xy^{\frac{3}{2} } + c[/tex]

therefore the gradient of F  i.e. F = vF  = F( x,y ) = [tex]6xy^{\frac{3}{2} }[/tex]

Next step : Determine the work done

Work done ( F.dr ) = [ F(point b ) = F( 3,4 ) ]  - [ F(point A) = F( 1,1 ) ]

F(3,4 ) = 6(3)(4)[tex]^{\frac{3}{2} }[/tex]  = 144

F( 1,1 )  = 6(1)(1)[tex]^{\frac{3}{2} }[/tex]    = 6

Therefore the work done by the force field = 144 - 6 = 138 J

Hence we can conclude that the work done by the force field F is = 138 J

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An example of a point source water pollutant is a sewer pipe draining directly into a river.

According to the United States Environmental Protection Agency, a  point source pollution is defined as;  “any single identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestack.”

Hence, an example of a point source water pollutant is a sewer pipe draining directly into a river. The pollution is coming from an easily identifiable source which is a sewer pipe connected to a river directly.

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Answer:

Torque = 50N x 0.3m = 15Nm

Explanation:

Torque = Force x length of lever arm. To obtain the torque simply multiply the two given values.

Answer: An ice hockey player picks up a trophy as he slides past it.

Two pool balls colliding precisely inelastically and rebounding off one another is an example. So, the correct option is A.

Inelastic collisions are those in which the total kinetic energy is lower after the impact than it was before. The stick is travelling quickly in the direction of the ball before to the contact. The stick comes to a stop following the accident. It transfers some of its kinetic energy to the cue ball, which rolls forward.

The type of collision mentioned in the given example is known as an inelastic collision is one in which the system's momentum is preserved but its kinetic energy is not. In a ballistic pendulum, an example of an inelastic collision. Dropped ball of clay is another illustration of an inelastic collision.

Thus, the correct option is A.

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Your question is incomplete, most probably the complete question is:

Which of the following statements describes a perfectly inelastic collision?

A. Two billiard balls bounce off of each other,

B. A car crashes into a tree and rebounds in the other direction,

C. A wad of chewing gum is thrown and sticks to a moving truck,

D. Two ice skaters hit each other and fall over in opposite directions,

Answer

An Achievement test is an assessment of developed knowledge or skill. ... Achievement tests are developed to measure skills and knowledge learned in a given grade level, usually through planned instruction, such as training or classroom instruction. Achievement tests are often contrasted with aptitude tests.

Explanation:

The magnet is attracted to the ring since the north pole of the current loop is above the ring and the south pole is below the ring.

The water in the bucket containing the aluminium block is warmer than the bucket containing the copper block.

The specific heat is the amount of heat needed or required to elevate the temperature of 1 gram of a substance by 1° C.

At standard conditions;

We know that:

Therefore, since the specific heat of aluminium is higher than that of copper, the water bucket containing aluminium block will be warmer than the bucket containing the copper block.  

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Let m₁ and m₂ be the masses of the two objects, and v₁ and v₂ their initial velocities. So

m₁ = 30.0 g = 0.0300 kg

m₂ = 13.0 g = 0.0130 kg

v₁ = + 20.5 cm/s = 0.205 m/s

v₂ = + 15.0 cm/s = 0.150 m/s

and we want to find v₁' and v₂', the final velocities of either object after their collision.

Momentum is conserved throughout the objects' collision, so that

m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'

where v₁' and v₂' are the first and second object's velocities after the collision.

Kinetic energy is also conserved, so that

1/2 m₁v₁² + 1/2 m₂v₂² = 1/2 m₁(v₁')² + 1/2 m₂(v₂')²

or

m₁v₁² + m₂v₂² = m₁(v₁')² + m₂(v₂')²

From the first equation (omitting units), we have

0.0300 • 0.205 + 0.0130 • 0.150 = 0.0300 v₁' + 0.0130 v₂'

0.0810 = 0.0300 v₁' + 0.0130 v₂'

81 = 30 v₁' + 13 v₂'

From the second equation,

0.0300 • 0.205² + 0.0130 • 0.150² = 0.0300 (v₁')² + 0.0130 (v₂')²

0.00155 ≈ 0.0300 (v₁')² + 0.0130 (v₂')²

1.55 ≈ 30 (v₁')² + 13 (v₂')²

Solving both equations simultaneously gives two solutions, one of which corresponds to the initial conditions. The other yields

v₁' ≈ + 0.172 m/s

and

v₂' ≈ + 0.227 m/s

Explanation:

I'm not sure, but I would go for the more than A since its orbital speed is at its fastest and the sweep occurs in about the same period of days.

Answer:

b, it's a pretty easy explanation

Answer:

1. C

2. True

3. D

4. True

Explanation:

While distance refers to “how much land an object has traversed throughout its journey,” displacement measures “how far an object is out of place.” In this post, let's look at the difference between distance and displacement. Thus, option C is correct.

Displacement and distance are two distinct ideas. The total distance travelled is larger than the displacement between those two points if an object changes direction while travelling.

Distance is the length of any path connecting any two places. Displacement is the straight-line distance between any two points when calculated along the shortest route.

Therefore, The direction is ignored when calculating distance. The direction is accounted for in the displacement calculation.

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