a girl on a bridge throws a rock straight down at -12.5 m/s. it hits the ground 38.4 m below. How much time did it take?

Answer:

If an object gains electrons it becomes positively charged.

Explanation:

Electrons negatively charge.

Answer:

θ = 90°

Explanation:

Speed at which she can swim in stationary water; v_m = 2 mi/h

Speed at which the river is flowing downstream; v_r = 1.5 mi/h

This can be illustrated in a form of triangle as attached. Where θ is the angle to the x-axis.

With respect to the bank of the river, the total speed of the girl is;

V_R = v_r + v_m

Now the horizontal component is;

V_R = v_r + v_m(cos θ)

While the vertical component is;

V_R = v_m(sin θ)

Now, the total time taken to get across the river is;

T = width of river/vertical component of total speed

Let's denote width of river as d.

Thus;

T = d/(v_m(sin θ))

Now, we are told she wishes o minimize the total time(T) .

Since the width(d) of the river is constant, and v_m is fixed, then it means the only variable we have is the angle θ.

Now, for the total time to be minimized, the denominator has to be at maximum.

Since angle θ is the only one that is variable, we have to find the value of angle θ that will make sin θ to be at a maximum value.

Now, for sin θ to be maximum, it means it has to be equal to 1.

Thus, θ = sin^(-1) 1

θ = 90°

Answer:

Sand and salt are poured into a single beaker. The result is a mixture because they can be separated by simple and easy physical means.

Explanation:

Mixture : Properties :

Now let us see these in the perspective of the question :

These are some few reasons why these getting mixed, becomes a mixture, and we can choose any one point of the properties of mixture and give the answer.

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Answer:

: An app thr features menu planning with healthy recipes and pairs with a calorie tracking tool

389wujh

which means it 240C

Answer: lightning is the occurrence of a natural electrical discharge of very short duration and high voltage between a cloud and the ground or within a cloud, accompanied by a bright flash and typically also thunder.

the causes of lightning:

Lightning happens when the negative charges (electrons) in the bottom of the cloud are attracted to the positive charges (protons) in the ground.

In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. When the opposite charges build up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning.

Answer:

s=25956m

Explanation:

first 37 km/h is 10.3 m/s

then 42 min is 2520s

finally s=vt => s=2520s*10.3m/s

s=25,956m

Answer:

25956

Explanation:

Convert 37km/h to m/s =10.3m/s

Where s=vt

S=10.3×2520

S=25,956

S=25,000

Answer:

When scientific knowledge changes overtime, it can be to anything at anytime. The Explosion in what we know about life form is important and change because we might have a plant we can’t touch or something like that. That is not the only thing that is important about how scientific knowledge change over time it is also the food pyramid. We know that especially The Explosion in What We Know About Life Forms, is because there might be like a new plant we can’t touch because say it is potions or something. According to the life forms article people are wondering if scientist have found all the living species on earth yet

Explanation:

Answer:

Stage one of sleep, also known as the transitional phase, occurs when one finds themselves floating in and out of consciousness. During this NREM stage, you may be partially awake while your mind begins to drift off. This period of drowsiness eventually leads to a light sleep

Explanation:

i found it on google

Answer:

Can you help me with another question

Explanation:

The electric current in the coil  depends on changes in the magnetic field of the magnet.

Electricity is generated when there is relative motion between a conductor and a magnetic field. As the magnet is being moved through the coil of wire, the magnetic flux around the conductor changes and current is induced on it.

Hence, the strength of the electric current in the coil is determined by  changes in the magnetic field of the magnet.

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Answer:

At the tip of the pistil

Explanation:

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Answer:

jjjjjjjjjjjjjjjj

Explanation:

Answer:

Negative Feedback...... Temperature

Explanation:

as the Temperature increase more than the set point the air conditioner turn on to lower the temperature so that means it is Negative feedback because it is not INHANCING the temperature

Input should be Temperature or Heat because AC turns on when the temperature is getting above 70 degrees

NOW WHERE IS MY BRAINLIESTTTT

Answer:

0.133 m/s²

Explanation:

F=ma
F is force
m is mass
a is acceleration

F=ma
2=15.a
a=2/15

a=0.133 m/s²

Answer:

v = ω R

number of seconds in 24 hrs = 24 * 3600 = 86400 s / da = T (period)

f = 1 / T

ω  = 2 Π f = 2 Π / T = 2 Π / 86400

v = 2 Π / 8.64E4 * 6.0E6 = 436 m / s

Check:

S = 2 Π * 6.0E6 = 3.77E7 m/da

S / T = 3.77E7 m/da / 8.64E4 s/da = 436 m / s

Given:-

Mass of boulder = 10kg

Final Velocity = 15m/s

Acceleration due to gravity = +10m/s

To Find:-

The kinetic energy of the boulder as it lands

The potential energy of the boulder when it was at the top of the cliff

The height of the cliff

Formulae used:-

Kinetic energy = mv²/2

Potential energy = mgh

Now,

We will first find the Kinetic enrgy,

→ K. E = ½mv²

→ K. E = ½ × 10 × (15)²

→ K. E = 5 × 225

→ K. E =1125J

But we know that when the body starts moving the Potential enrgy of the body starts Converting into Kinetic enrgy. Before reaching to the last spot it has equal kinetic energy and Potential energy.

Therefore,

→ mgh = 1125J

The Potential enrgy of the boulder when it was on top is 1125J

Now,

→ mgh = 1125J

→ 10 × 10 × h = 1125J

→ 100h = 1125J

→ h = 1125/100

→ h = 11.25m

Hence, The Height of the Cliff is 11.25m

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Answer: (c) solar cell

Explanation:

1 wrapping the coil around a piece of iron (such as an iron nail)

2 adding more turns to the coil.

3 increasing the current flowing through the coil.

The vector force on the unit positive charge placed at any location in the field defines the strength of the electric field at that point. The charge used to determine field intensity (field strength) is known as the test charge. Now, a field line is defined as a line to which the previously mentioned field strength vectors are tangents at the relevant places. When we study positive charge field lines, the field strength vectors point away from the positive charge. If there is a negative charge anywhere in the vicinity, the field lines that began from the positive charge will all terminate at the negative charge if the value of the negative charge is the same as the value of the positive charge. Remember that the number of field lines originating from positive charge is proportional to the charge's value, and similarly, the number of field lines terminating at negative charge is proportionate to the charge's value. As a result, if all charges are equivalent, all lines originating from the positive charge terminate at the negative charge. If the value of the positive charge is greater than the value of the negative charge, the number of lines ending at the negative charge will be proportionally less than the number of lines beginning at the positive charge. The remaining lines that do not end at the negative charge will go to infinity. If the positive charge is less, all lines from it terminate at a negative charge, and any other reasonable number of ines terminate at a negative charge from infinity. We should also keep in mind that the number of lines that run perpendicular to the field direction across a surface of unit area is proportional to the field strength at that location. As a result, lines are dense in the strong field zone and sparse in the low intensity region.

Answer:

11.25 J

Explanation:

GPE=wxh=80kg over 900m=11.25 J

Answer:

The required work done is [tex]6.5\times10^{9}\ J[/tex]

Explanation:

Given that,

Mass of each satellites = 940 kg

Altitude of A = 4500 km

Altitude of B = 11100 km

We need to calculate the potential energy

Using formula of potential

[tex]U_{A}=-\dfrac{Gm_{A}m_{E}}{r_{A}}[/tex]

Put the value into the formula

[tex]U_{A}=-\dfrac{6.67\times10^{-11}\times940\times5.98\times10^{24}}{6.38\times10^{6}+4.50\times10^{6}}[/tex]

[tex]U_{A}=-3.44\times10^{10}\ J[/tex]

We need to calculate the potential energy

Using formula of potential

[tex]U_{B}=-\dfrac{Gm_{B}m_{E}}{r_{A}}[/tex]

Put the value into the formula

[tex]U_{B}=-\dfrac{6.67\times10^{-11}\times940\times5.98\times10^{24}}{6.38\times10^{6}+11.10\times10^{6}}[/tex]

[tex]U_{B}=-2.14\times10^{10}\ J[/tex]

We need to calculate the value of [tex]k_{A}[/tex]

Using formula of [tex]k_{A}[/tex]

[tex]k_{A}=-\dfrac{1}{2}U_{A}[/tex]

Put the value into the formula

[tex]k_{A}=\dfrac{1}{2}\times3.44\times10^{10}[/tex]

[tex]k_{A}=1.72\times10^{10}\ J[/tex]

We need to calculate the value of [tex]k_{B}[/tex]

Using formula of [tex]k_{B}[/tex]

[tex]k_{B}=-\dfrac{1}{2}U_{B}[/tex]

Put the value into the formula

[tex]k_{B}=\dfrac{1}{2}\times2.14\times10^{10}[/tex]

[tex]k_{B}=1.07\times10^{10}\ J[/tex]

We need to calculate the work done

Using formula of work done

[tex]W=\Delta K+\Delta U[/tex]

[tex]W=(k_{B}-k_{A})+(U_{B}-U_{A})[/tex]

[tex]W=(-\dfrac{U_{B}}{2}+\dfrac{U_{A}}{2})+(U_{B}-U_{A})[/tex]

[tex]W=\dfrac{1}{2}(U_{B}-U_{A})[/tex]

Put the value into the formula

[tex]W=\dfrac{1}{2}\times(-2.14\times10^{10}+3.44\times10^{10})[/tex]

[tex]W=6.5\times10^{9}\ J[/tex]

Hence, The required work done is [tex]6.5\times10^{9}\ J[/tex]

Answer:

Explanation:

What was the answer Im stuck on it rn...

Answer:

Changes in fluid power systems lead to increased sustainability, such as decreases in fuel costs and carbon emissions.

Explanation:

Answer:

120 mph

Explanation:

Given:

Δx = 0.25 mi

v₀ = 0 mi/s

t = 15 s

Find: v

Δx = ½ (v + v₀) t

0.25 mi = ½ (v + 0 mi/s) (15 s)

v = 0.0333 mi/s

v = 120 mi/h

Answer:

1. Acceleration begins to slow down quickly

2. Kenetic

3. Mass

Answer:

Acceleration slows down

Kinetic

Mass

Explanation:

Since the winner's average speed was about 318 km/h and the kinetic energy of the winning car was 3.80 MJ. So, the mass of the car and its driver is 974 kg.

The kinetic energy of the car is given by K = 1/2mv² where

Making m subject of the formula, we have

m = 2K/v²

Since K = 3.80 MJ = 3.80 × 10⁶ J, substituting the values of the variables into the equation, we have

m = 2K/v²

m = 2 × 3.80 × 10⁶ J/(88.33 m/s)²

m = 7.6 × 10⁶ J ÷ (7802.78 m²/s²)

m = 7600000 J ÷ 7802.78 m²/s²

m = 974.01 kg

m ≅ 974 kg

So, the mass of the car and its driver is 974 kg

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Answer:

0.5 mA,  step-up transformer

Explanation:

Power is constant

V * I = constant

500 V * 10 mA = 10,000 V * I

so I = 0.5 mA

From 500 V increases to 10,000 V, so it is a step-up transformer

Change in momentum of the ball is 74.8 kg m/s

change in velocity of the ball is 0.25 m/s

Change in momentum is the product of mass and change in velocity this is also equal to impusle which ia a product of force and time.

Change in momentum = m ( v - u ) = Impulse = f * t

m = mass

change in velocity = v - u

v = final velocity

u = initial velocity

f = force

t = time

Given:

f  = 187 N

m = 7.3 kg

t = 0.40 s

!.

Change in momentum = impulse = f * t

Change in momentum = 187 * 0.40

Change in momentum = 74.8 kg m/s

2.

Change in momentum = m * ( v - u )

( v - u ) = change in momentum / m

( v - u ) = 187 / 7.3

( v - u ) = 10.25 m/s

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Answer:

As traditionally used, impairment refers to a problem with a structure or organ of the body; disability is a functional limitation with regard to a particular activity; and handicap refers to a disadvantage in filling a role in life relative to a peer group.

Explanation:

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