Bob who has a mass of 100 kg stands ona. Frictionless frozen lake with a 20 kg rock in his hands. He throws the rock forward with a velocity of +5 m/s. What is the velocity of bob after he throws the rock

A. -2 m/s
B. -1 m/s
C. 0 m/s
D. 1 m/s

Answers

Answer 1

Answer:

Option B

Explanation:

This involves the conservation of momentum:

m1v1 = m2v2

Now initially neither the rock nor Bob is moving. Then the rock moves forward with a velocity of 5 m/s, having a mass of 20 kg. But Bob moves back by the conservation of momentum, so at what velocity?

0 = 20(5) + 100(vf),

-100 = 100vf,

vf = - 1m/s


Related Questions

A motorcycle engine provides 473.3 N of force for 11.9 seconds. If the rider and the cycle have a mass of 2,068.3 kg, determine the change in velocity.​

Answers

Answer:

After 11.9 seconds, the velocity will increase by approximately 2.7 m/s

Explanation:

Ignoring friction, we can simply say that the speed will increase by

11.9s × 473.3N / 2068.3kg

Which can be expressed as:

11.9s × 473.3kg·m/s² ÷ 2068kg

= (11.9 × 473.3 ÷ 2048.3) (kg·m/s² × s ÷ kg)

≈ 2.7 m/s

Which example of heat transfer is due mainly to convection?

Answers

An oven I think sorry if I’m wrong

A big kid pushes a little kid and the little kid falls backward. The big kid remains relatively stationary. What best explains this

Answers

The big kid is the strongest ?

Answer:

Becase he pushed the little kid not himself

Explanation:

If a certain test follows a normal curve, most of the scores will fall
A. at the top end
B. at the bottom end
C. all over the place
D. in the middle
Please select the best answer from the choices provided
Ο Α
OB
С
OD

Answers

i think the answer is b

Answer:

im pretty sure its d

Explanation:

1. what is the average speed after two seconds?

2. after three seconds?

3. after 5 seconds?

4. what is the average speed between two and four minutes?

5. what is the average speed between four and five minutes?​

Answers

Answer:

1. 75 speed, 2. 90 second = 1hr. 30 second. 3. 125 = 1hr 60 seconds 4.

b. Find the velocity of a rider on the ride.
Given:

a =

r =

Unknown:

V =?

Equation:

a = v^2/r

Or

v^2 = a*r

Solution

Answers

D

Explanation:

Mutiply and alagrab to subterc

What will most likely happen if a sound wave moves from the air through a solid?

It will increase in wavelength.
It will decrease in speed.
It will increase in speed.
It will decrease in wavelength.

Answers

C. It will increase in speed
It will increase in speed, so it is the third option! Hope this helped!

three advantages of simple machines.please tell fast​

Answers

Answer:

they can help make clothing, they are useful for human like work, they are better than hand making

Which statement about this figure is false


A. Line E represents a fault line.


B. Layer C is the youngest layer.


C. d,ike K is older than layer I.


D. The fault occurred after layer F formed.

Answers

The statement about the figure that is false is that d,ike K is older than layer I. That is option C.

What is cross-cutting relationships in geology?

Cross-cutting relationships is a principle that when a body pass through different layers in geology, it is usually younger than all the layers it passed through.

That is to say that, d,ike K is younger than layer I, D and B which it passed through.

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Answer:

If it's not C then it HAS to be B.

Explanation:

By deductive reasoning.

what substance is used by plants as a source of food

Answers

Answer:

dart

Explanation:

dart and sun and water so that the plant be okay

7. The S.l. unit for force is
A. kg
C. m/s
B. m/s2
D. N

Answers

D.N(Newton) this is the S.I unit for force

The Big Bang Theory was supported by the discovery of the

red shift in electromagnetic spectrum

gravitational force between planets

temperature of the universe

galaxies in the universe

Answers

Two major scientific discoveries provide strong support for the Big Bang theory: • Hubble's discovery in the 1920s of a relationship between a galaxy's distance from Earth and its speed; and • the discovery in the 1960s of cosmic microwave background radiation. Please give brainliest

How fast is a 85 kg football player moving if they have a momentum of 125 kg*m/s?

Answers

Answer:

v = 1.5 m/s

Explanation:

m = 85 kg

p = 125 kg m/s

v = ?

p = m v

125 kg m/s = (85 kg) (v)

v = (125 kg m/s) / (85 kg)

v = 1.47 m/s

why is measurement important?​

Answers

Answer:

Measurement is important so we could measure certain things right. By taking measurements we can have a knowledge of sizes, lengths, widths etc.

Explanation:

A box on the ground is being pulled from the left and right by string. The box is accelerating to the left. What five forces are being used?

Answers

Answer:

push and pull,kinetic energy,force,and motion. I hope this helped if I get you this question wrong I deerly aploizge.

What is a direct result of having greenhouse gases in the atmosphere?

Answers

Answer:

Well this is tough. I'm not sure but you are smart and can push through it. YOU DONT need the someone telling you the answer when it is inside you.

hope this helps p

Carbon dioxide would be what is put within the atmosphere

Does anyone know how to do this pleaseeeee

Answers

Answer:

See the answer below.

Explanation:

The latent heat of fusion is defined as the amount of energy needed to make a phase change from solid to liquid. And it can be calculated by means of the following expression:

[tex]Q_{fusion}=m*Dh[/tex]

where:

Qfusion = Heat Energy [J]

m = mass = 0.65 [kg]

Dh =  latent heat fusion = 330000[J/kg]

[tex]Q_{fusion}=0.65*330000\\Q_{fusion}=214500[J][/tex]

2)

We know that energy can be calculated from power, where power is defined as the relationship between energy over time.

[tex]P=E/t[/tex]

where:

P = power = 60 [w]

E = energy [J]

t = time = 5 [min] = 300 [s]

[tex]E=P*t\\E=50*300\\E=15000[J][/tex]

The mass change due to the process is equal to:

[tex]m=282-274\\m=8[g]=0.008[kg][/tex]

Now using the following equation for the latent heat of Fusion, we can calculate this value:

[tex]Q=m*Dh\\Dh =Q/m\\Dh=15000/0.008\\Dh=1875000[J/kg][/tex]

How does energy travel? Where is the initial source of energy in our solar system? What is the process that gives off energy from the sun called?

Answers

Answer:

How does energy travel?

One way the energy can travel is through radiation. An object can radiate energy in the form of electromagnetic waves, for example when a strong light is turned on and you can feel some heat coming from it, or when you walk under the sunlight and you can feel the heat in your skin.

Where is the initial source of energy in our solar system?

In the solar system, the source of energy comes from the Sun, and the sun irradiates that energy to all the nearby objects.

What is the process that gives off energy from the sun called?

The process is called radiation, this is all the energy that comes from the sun in the form of different electromagnetic waves (light in the visible range, UV rays, etc...)

A boy and a girl are balanced on a massless seesaw. The boy has a mass of 75 kg and the girl's mass is 50 kg. If the boy sits 2.0 m from the pivot point on one side of the seesaw, where must the girl sit on the other side?

Answers

Answer:

The girl must sit 5 m on the other side of the seesaw.

Explanation:

Given;

mass of the boy, = 75 kg

mass of the girl, = 50 kg

distance of the boy from the pivot, = 2 m

let the distance of the girl from the pivot = d

    <-------------2m-------------><-------------d-------------->

-----------------------------------------------------------------------------------

     ↓                                  Δ                                   ↓

     75                                                                      50

Apply the principle of moment, about the pivot;

clockwise moment = anticlockwise moment

75 x 2 = 50 x d

150 = 50d

d = 150 / 50

d = 3 m

The distance of the girl from the pivot is 3 m.

Therefore, the girl must sit ( 2m + 3m ) on the other side of the seesaw.

Imagine you are an astronomer who recently discovered a new planet orbiting a distant star. Which set of characteristics would you use to classify this planet as an inner or terrestrial planet? Check all that apply.
-dense and solid
-very large
-thick atmosphere containing hydrogen and helium
-lacking a solid surface
-located near a star

Answers

Answer:

The right characteristics to be used for the classification include:

-dense and solid

-very large  

-located near a star

Explanation:

The above listed characteristics are part of the characteristics used in classifying a planet as a habitable planet or non-habitable one. When a planet is closer to a star which revolves around it, this helps in supplying the needed light to it.

Answer:

dense and solid

located near a star

Explanation:

a tree is blank relative to earth a tree is blank relative to the sun

Answers

hmmmmmmmmmmmmmmmmm ask someone else sorry if im not helping

Determine the mass of a boat that is propelled forward by a force of 1250N at an acceleration of 3 m/s2.

Answers

Answer:

416.6 KG

Explanation:

Due to the mass being missing from the equation you divide the force by the acceleration

Please Help Me!!!.......​

Answers

Answer:

D

Explanation:

Water has a high surface tension because the water molecules on the surface are pulled together by strong hydrogen bonds. That means a drop of water will "want" to have the smallest possible surface area.

Stephanie is in volleyball practices and she notices something interesting about the
effect that spiking the ball has on her hand. She notices that the harder she hits the
ball, the more that her hand hurts afterward. Which Newton's Law explains why this
happens?

Answers

Newton’s Second law

The Newton's law that explains the reason for the pain experienced by Stephanie when she spikes the ball is Newton's third law of motion.

Newton's third law of motion, states that, action and reaction are equal and opposite.

The force exerted on the ball when Stephanie spikes is equal to the reaction the ball exerts back on Stephanie. As the force Stephanie applied increases, the reaction she receive from the ball increases as well and the more pain she will feel.

Thus, we can conclude that, the Newton's law that explains the reason for the pain experienced by Stephanie when she spikes the ball is Newton's third law of motion.

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Which is a possible result of rising ocean temperatures caused by global warming?

formation of dust bowls
increase in strength of hurricanes
rapid evaporation of water in soil
decrease in population due to health threats

Answers

Answer:

Increase in strength of hurricanes

Explanation:

A possible result of rising ocean temperatures caused by global warming is an increase in the strength of hurricanes, which is the second option. As the ocean temperatures increase, more energy is available to fuel hurricanes, making them stronger and potentially more destructive.

What is global warming?

Global warming is causing the earth's climate to change, which is having a significant impact on the world's oceans. As the temperature of the oceans increases, a variety of effects can occur. One of the most well-documented impacts is the increase in the strength of hurricanes. Hurricanes form over warm ocean waters, and as the water temperature rises, it provides more energy to the storm, making it more powerful. 

Hence, a possible result of rising ocean temperatures caused by global warming is an increase in the strength of hurricanes, which is the second option.

Learn more about global warming here.

https://brainly.com/question/20632812

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The current flowing through the heating element when a toaster is plugged into a 230V mains supply, if the element has a resistance of 265Ω.

Answers

Answer:

The current flowing the heating element is 0.868 amperes.

Explanation:

Ohm's law states that voltage is directly proportional to current. In other, words, we say that:

[tex]V \propto R[/tex]

[tex]V = i\cdot R[/tex] (1)

Where:

[tex]V[/tex] - Voltage, measured in volts.

[tex]i[/tex] - Current, measured in amperes.

[tex]R[/tex] - Resistance, measured in ohms.

If we know that [tex]V = 230\,V[/tex] and [tex]R = 265\,\Omega[/tex], then the current that flows through the heating element is:

[tex]i = \frac{V}{R}[/tex]

[tex]i = \frac{230\,V}{265\,\Omega }[/tex]

[tex]i = 0.868\,A[/tex]

The current flowing the heating element is 0.868 amperes.

In which stage of sleep are you likely to experience hypnagogic
sensations of falling asleep

Answers

NREM-1 got this off a website

Explained and elaborate further the function of assessing responsiveness

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If a person is down or ill you may need to constantly check if their responsive as they my be suffering from a silent killer and can die

You are researching a fungus that can kill banana plants. Which source is
likely to have the least reliable information?
A. An article in a popular science magazine
B. A press release about research on the fungus posted on the
website of a university
C. A posting about the fungus on a social media site
D. A report about the fungus on a nightly news show

Answers

Answer:

B

Explanation:

what could i say except ur welcome

What happens to the energy when the material is changed?

Answers

Answer: When a material is heated or cooled, two changes may happen to the particles within the material: Chemical bonds between the particles may form, break or stretch. There is a change in the chemical potential store of energy in the material. The material will heat up or cool down as the particles within it gain or lose speed.

Explanation:

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