A 40kg girl and a 50kg boy are facing each other on a friction-free rollerskates. The girl pushes the boy, who moves away at a speed of 3 m/s. What is the girl's
speed?
Your answer

Answers

Answer 1

Answer:

Explanation:

The Law of Momentum Conservation, just like the Law of Thermodynamics about energy, says that momentum is neither created nor destroyed but is conserved, meaning it has to go somewhere. If the girl pushes the boy and they are both on friction free skates, then the girl will also react to the push. Momentum Conservation says

[tex](m_gv_g+m_bv_b)_b=(m_gv_g+m_bv_b)_a[/tex] In words this says that the mass times the velocity of the girl plus the mass times the velocity of the boy before the push has to equal the mass times velocity of the girl plus the mass times velocity of the boy after the push. Mathematically,

[tex](40.0*0+50.0*0)_b=(40.0v+50.0*-3)_a[/tex]

The left side of this is equal to 0. On the right, I made the velocity of the boy negative. We could have made it positive and it wouldn't have mattered. The sign will only be important to the result because if the sign of the girl's velocity is the same as the boy's, she is moving in the same direction as he is; if it's different, she is moving in the opposite direction.

0 = 40.0v - 150.0 and

-40.0v = -150.0 so

v = 3.75 This means that when she pushes the boy one way, mometum is conserved and she moves in the opposite direction and at a greater velocity (because her mass is less). Physics is a wonderful thing, isn't it!?


Related Questions

What nuclear reaction is shown in the equation below

Answers

Answer:

nuclear fission

Explanation:

nuclear fission

Answer: Nuclear fission

Explanation:

Select the correct answer
If the resistance in a circuit remains constant, what happens to the electric power when the current increases?
OA. The power will increase.
OB.
The power will decrease,
OC. There will be no power.
OD
The current does not affect the power,
Reset
Next

Answers

Answer :

[tex]\large\mathrm{A. Power\:\: will \:\:Increase }[/tex]

Explanation :

We know that,

[tex]\large \mathrm{ \boxed{P = I²R}}[/tex]

where,

P = electric powerR = resistanceI = electric current

And when resistance is constant, the power of the circuit will change proportionally with the change in electric current. therefore, if current increases then the electric power of the circuit will increase too.

[tex]\large\mathfrak{{\pmb{\underline{\orange{hope \: \: i t \: \: helps \: \: you}}{\orange{.....}}}}}[/tex]

I am confused and need help with the question above??

Answers

It’s b it’s going clockwise

Convergent boundaries are responsible for

Answers

Answer:

A

Explanation:

The plate collisions that occur in these areas can produce earthquakes, volcanic activity, and crustal deformation.

hope it helps you

A motor has an internal resistance of 12.1 Ω. The motor is in a circuit with a current of
4.0 Amps
What is the voltage?

Answers

Answer:

Explanation:

V = I * R

V = 4 * 12.1 = 48.4 v

A trip is taken that passes through the following points in order
Point A Om
Point B 15.0 m
Point C -30.0 m
Point D 20.0 m
Point E -10.0 m
Point F 5.0 m
What is the displacement from Point B to Point E?

A) 5.0 m right
B) 85 m right
C) 25.0 m left
D) 85 m left

Answers

Answer:

The displacement from point B to point E is 25.0 m left

electromotive force in a circuit;
A) causes free electrons to flow
B) increases the circuit resistance
C) maintains circuit resistance
D) it needed to make the circuit complete

Answers

Answer:

A causes free electrons to flow

Explanation:

The amount of force that causes electrons to flow in a conductor is called electromotive force.

what current flows between a voltage of 120v across a resistance of 30Ω?​

Answers

Answer:

4 amp

Explanation:

From ohm's law,

V=IR

so,

I=V/R

I=120/30

I=4amp ans..

5. What type of chemical reaction is shown?
1 point
2 AgNO3 + CuCl2
-
2 AgCl + 2 Cu(NO3)2
Synthesis
Decomposition
Singe Replacement
Double Replacement
Combustion

Answers

Answer:

double Replacement

Explanation:

The mutual replacement of radical and ions between the two compounds or molecules is called double replacement.

General equation : AB+CD = AD +B

hey everyone


what is optics??​

Answers

Explanation:

Optics is a branch of physics that is the study of light and vision. ... The branch of physics dealing with the nature and properties of electromagnetic energy in the light spectrum and the phenomena of vision. In the broadest sense, optics deals with infrared light, visible light, and ultraviolet light.

Amelia is doing an experiment in which she is
going to burn various solid chemicals to see the
colors of flames they produce. For this laboratory
experiment, what types of safety precautions
should she take?
tie hair back
leave open flame unattended to get a drink
only burn the amount of chemicals as
directed by the lab procedure
put out the flame with water from the eyewash
station

Answers

Answer:

tie hair back

only burn the amount of chemicals as

directed by the lab procedure

Explanation:

The correct safety precautions for Amelia to take from the options would be to tie her hair back and to only burn the amount of chemicals recommended by the lab procedure.

With her hair left flowing freely, Amelia runs the risk of the hair catching flame while trying to burn the chemicals according to the procedure. Hence, tying her hair up into one neat bunch will limit the risk of it catching fire while working in the lab.

Also, burning less or more than the amount of chemicals recommended by the procedure may be dangerous or hinder Amelia from getting the right result.

Answer:

1,3

Explanation:

just did it

Q) A farmer moves along the boundary of a
square field of side 10 min 40 s .What will
be the magnitude of displacement of the
farmer at the end of 2 minutes 20 seconds
from his initial position?​

Answers

The answer will be 8 because kedks

5. A wire, resistance 23.6 carries a current. 5.9 A. What is the
potential difference across the wire?
a. V = 139 V
c. V=4V
b. V = 17.7 V
d. V = 0.25 V

Answers

Answer:

d

Explanation:

Answer:

B

Explanation:

A positively charged rod is brought close to a neutral metal sphere. Explain what
happens to the charges in the neutral sphere as the rod comes close, touches the
sphere, and then moves away. Is the metal sphere still neutral at the end of this
encounter?

Answers

Answer:

No, the metal sphere becomes positively charged because electrons are transferred from the sphere to the rod.

give an example of a body with uniform acceleration​

Answers

Answer:

A ball rolling down the slope.

A bicycle rider is riding the bicycle on tthe slope where both pedals are engaged.

When the surface of a metal is exposed to blue light, electrons are emitted. If the intensity of the blue light is increased (so the light is just brighter), what value will also increase?
A. the maximum kinetic energy of the ejected electrons
B. the number of electrons ejected per second
C. the time lag between the onset of the absorption of light and the ejection of electrons

please help!!!

Answers

So, we know that this question is about photoelectric effect.

What is photoelectric effect?

-Photoelectric effect is a phenomenon where electrons are released from a material whenever an electromagnetic radiation such as light, hits it.

-This phenomenon is first discovered by Heinrich Rudolf Hertz in 1887 whereas Albert Einstein, in 1905, resolved the conflict between the photoelectric effect and Maxwell's electromagnetic wave theory of light.

Now to your question, the intensity of light only determines the number of the electrons released, not their maximum kinetic energy because this are proportional to the light's frequency.

Also, there is no time lag detected between the entry of radiation and the emission of electrons in experiments held.

So, with letter A and C out, we can therefore conclude that the answer for this is Letter B

The correct answer is B: the number of electrons ejected per second

The Einstein photoelectric equation states that;

[tex]KE = hf - hfo[/tex]

Where

KE = kinetic energy of the ejected photo electrons

h = Plank's constant

f = frequency of incident light

fo = threshold frequency.

The kinetic energy of ejected photoelectrons depends on frequency of incident photon and not on the intensity of the incident photon.

However, the number of photoelectrons ejected per second depends on the intensity of the incident blue light.

https://brainly.com/question/9260704

The two waves shown here are the same distance from point X and are traveling toward each other.

An illustration with a crest 2.0 centimeters high traveling to the right and a second 2.0 centimeters trough traveling toward the left toward point X in the material.
What is the amplitude of the resulting wave when the two waves meet at point X?

0.0 cm
1.0 cm
2.0 cm
4.0 cm

Answers

Answer:

(C) on edge.

Explanation:

Answer:

2.0

Explanation:

trust the process.

Derive the relation between wavelength, frequency and speed of sound.​

Answers

Explanation:

sorry I need some points foe this

Calcalculate potential energy given to a potato sack having a mass of 2 kg as I raise it to a height of 450 CM ​

Answers

Answer:

8.829 Joules

Explanation:

The potential energy of an object, is the energy it posses (the energy stored within the object) by virtue of its relative elevation or height, position, state, or arrangement

The potential energy of an object raised to a given height, P.E. = m·g·h

Where;

m = The mass of the object

g = The acceleration due to gravity, a constant ≈ 9.81 m/s²

h = The present height of the object

For the potato sack having a mass, m = 2 kg, and raised to a height, h = 450 cm = 0.45 m, we have;

The potential energy given to the potato sack, by raising its height, P.E. is given as follows;

P.E. = 2 kg × 9.81 m/s² × 0.45 m = 8.829 Joules

The potential energy given to the potato sack, P.E. = 8.829 Joules


A car has a kinetic energy of 103kJ.
The speed of the car is 13.1 m/s.
Calculate the mass of the car.
Give your answer to 2 significant figures.

Answers

Answer: 1200kg

Explanation:

KE = (1/2)mv^2

103kJ = 103000J

103000J = (1/2) * m * (13.1m/s)^2

Solve for m

A car has a kinetic energy of 103kJ, and the speed of the car is 13.1 m/s,then the mass of the car would have been 1200 kilograms.

What is mechanical energy?

Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total stored energy in the system which is represented by total potential energy.

A car has a kinetic energy of 103 kJ. The speed of the car is 13.1 m/s,

The kinetic energy of the car = 1/2 × mass × velocity

                                     103000 =0.5 × mass × (13.1) ²

The mass of the car = 1200 Kilogram

Thus, if a car has a kinetic energy of 103kJ, and the speed of the car is 13.1 m/s,then the mass of the car would have been 1200 kilograms.

To learn more about mechanical energy, refer to the link;

https://brainly.com/question/2409175

#SPJ5

Please help me :))

Which golf ball would hit the surface with the greatest impact: a ball that fell one meter above the surface of the Earth or a ball that fell one meter above the surface of the Moon?

Answers

Answer:

the one above the surface of earth

Explanation:

earth has gravity the ball of the moon would float away

According to Archimedes' principle, when will an object float in water?
A. When its volume is less than the volume of water it displaces
B. When its weight is equal to the buoyant force exerted by the water
C. When its density is greater than the density of water
D. When its weight is greater than the weight of water it displaces

Answers

C. When it’s density is greater than the density of water.

Answer:

Its B

Explanation:

a p e x

please helpppp... thank u ❤️​

Answers

Answer:

For Ryan:

[tex]at \: highest \: point : v = 0 \\ velocity = 0 \: {ms}^{ - 1} [/tex]

For the football kicked:

[tex]s = ut - \frac{1}{2} g {t}^{2} \\ for \: range : s = 0 \\ u \sin( \theta) = \frac{gt}{2} \\ t = \frac{2u \sin(\theta) }{g} \\ range(x) = ut \\ x = \frac{ {2u {}^{2} \sin(\theta) }^{} }{g} \\ \frac{50 \times 9.8}{ {2318.9}^{} } = \sin(\theta) \\ \\but \: 0 = u \sin(25) - 2 \times 9.8 \times 50 \\ u = 2318.9 \: {ms}^{ - 1} \\ \theta = 12.2 \degree[/tex]

Answer:

the highest point for the first question is 0 meters per second

the answer for question 2 is 45 degrees

Using a 100 year time frame,what is the CO2e of 1 tonne of CO2,2 tonne or methane,and 3 tonnes of nitrous oxide

Answers

Well, let's see what we've got here:

                    ( 4⁻³ · 3⁴ · 4² )  /  ( 3⁵ · 4⁻² ) .

The two simple rules of exponents that we're

going to use here are:

-- Two multiply two numbers with the same base,

add their exponents.    Like   (A³) · (A²) = A⁵ .

But the bases have to be the same.

-- A negative power just means it belongs in the

other section of a fraction.

  A negative power on top means it belongs on the bottom.

  A negative power on the bottom means it belongs on top.

  Like    A⁻²  means  1/A² .  And  1/B⁻³  means  B³ .

That's all you need in order to clean up the big fraction

in the question.  But in order to see where you can use

these rules, you need to re-arrange things first.

Original:                          ( 4⁻³ · 3⁴ · 4² )  /  ( 3⁵ · 4⁻² )

Let's send the  4⁻³

to the bottom

where it belongs:              (   --  3⁴ · 4² )  /  4³ · ( 3⁵ · 4⁻² )

Not take that  4⁻² from

the bottom, and put it on

top, where it belongs:       (  4² · 3⁴ · 4² )  /  4³ · ( 3⁵    -- )

Multiply the 4²s on top:     (  4⁴ · 3⁴       )  /  ( 4³ · 3⁵ )

Now let me break this up.

Not changing anything, just

writing it in a different way:      ( 4⁴  /  4³ ) · ( 3⁴ / 3⁵ )

Look at the first fraction:  4⁴ / 4³ .

Divide top and bottom by  4³ , and it becomes just  4 .

Now look at the second fraction:  3⁴ / 3⁵ .

Divide top and bottom by  3⁴ , and it becomes just  1/3 .

So in the end, we're left with just      4 / 3 .

And THAT is exactly equal to the original big messy fraction

in the question.  It has exactly the same numerical value, but

you'd never know it when you see it, because it's a lot simpler.

There are a lot of other ways we could have manipulated and

massaged the original fraction, but the steps are the same:

-- Multiply numbers with the same base, by adding the exponents.

-- Remember that a number with a negative exponent belongs

in the other section of the fraction, with a positive exponent.

As an IT technician for your company, you have been notified that the Windows domain does not seem to be functioning properly. Being familiar with domains, you are fairly confident you know what the issue is. But just to be safe, you take the applicable time to gather additional information and to identify what, if anything, has changed.

Which of the following is the BEST next step?

A. Determine the appropriate fix.
B. Create a hypothesis.
C. Implement the fix.
D. Identify what has changed.
E. Gather information.

Answers

Answer: Create a hypothesis

Explanation:

From the information given, information has been gathered and the identification to ascertain if there's a change. Then, an hypothesis has to be created in order to know what the problem is.

One has to carry out some research in order to know what went wrong and should also validate the hypothesis by consulting with ones peers. By doing this, the most likely causes of the issues will be gotten.

What is the three-body problem? Explain at a level so an 8th grader could understand

Answers

Answer:

In physics and classical mechanics, the three-body problem is the problem of taking the initial positions and velocities (or momenta) of three point masses and solving for their subsequent motion according to Newton's laws of motion and Newton's law of universal gravitation.[1] The three-body problem is a special case of the n-body problem. Unlike two-body problems, no general closed-form solution exists,[1] as the resulting dynamical system is chaotic for most initial conditions, and numerical methods are generally required.

Hope this answer is right!

A meterstick is placed on a pivot point of 42.5cm and a 45g mass is hung at the 20cm mark. When released the meterstick remains in static equilibrium. What is the mass of the meterstick

Answers

Hey i dont have an answer but i need the points for finals today. Thank you
I don’t know the answer sorry I need points

What's the meaning of longitudinal?

Answers

Answer:

A longitudinal study is a research design that involves repeated observations of the same variables over short or long periods of time. It is often a type of observational study, although they can also be structured as longitudinal randomized experiments.

Explanation:


If you want to decrease the current created by a generator what can you do?

Answers

Answer:

To decrease the current;

1) Use fewer loops or number of turns

2) Use a lower speed of rotation of the coil in the magnetic field

3) Use a weaker magnetic

Explanation:

According to Faraday's Law of induction, which is the basis of the electromagnetism, electromagnetic induction and therefore the basis of the  electric generator, can be written as follows;

[tex]\epsilon = -N \cdot \dfrac{\Delta \phi}{\Delta t}[/tex]

Where;

ε = The induced voltage

N = The number of turns (loops)

ΔФ = The change in the magnetic flux

Δt = The change in the time (the duration)

Given that voltage is directly related to the current, decreasing the voltage, decreases the current

To decrease the voltage, and therefore, the current we can;

1) Reduce the number of loops in the coil

2) Increase the time change per unit change in flux by slowing down the speed of rotation of the generator

3) Decrease the amount of change in the magnetic field per turn, by using a weaker magnetic

Which state has the most fixed shape?
O A. Gas
O B. Solid
O C. Liquid
O D. Plasma

Answers

Answer: Liquid

“A substance will take on the shape of an open container if it is a Liquid. Explanation: The major state of matter are solid, liquid and gas. Liquid usually have a definite volume.”

Answer:

solid

Explanation:

Solids are fixed and solid.

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