A man is sitting on a chair with wheels. He grabs a 2.1 kg book from the desk and throws
the book at a speed of 7.2 m/s. His chair moves backward. The man has a mass of 70 kg and
the chair has a mass of 9.2 kg. What is the speed of the man and the chair after the book is
thrown?

Answers

Answer 1

The speed of the man and the chair after the book is thrown is 0.2 m/s.

The given parameters:

mass of the book, m₁ = 2.1 kgspeed of the book, u₁ = 7.2 m/smass of the man, M = 70 kgmass of the book, m = 9.2 kg

The total mass of the man and the book is calculated as follows;

m₂ = 70 kg + 9.2 kg

m₂ = 79.2 kg

The speed of the man and the chair after the book is thrown is determined by applying the principle of conservation of linear momentum;

[tex]m_1 u_1 = m_2u_2\\\\u_2 = \frac{m_1u_1}{m_2} \\\\u_2 = \frac{2.1 \times 7.2}{79.2} \\\\u_2 = 0.2 \ m/s[/tex]

Thus, the speed of the man and the chair after the book is thrown is 0.2 m/s.

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Related Questions

The c-c sigma bond in acetylene is formed by the overlap of which two orbitals.

Answers

Answer:When carbon atom tends to form single bonds then its hybridization is , when carbon atom tends to form double bond then its hybridization is  and when a carbon atom is attached to a triple bond or with two double bonds then its hydridization is sp.

For example, in HCN molecule there is a triple existing between the carbon and nitrogen atom.

So, hybridization of carbon in this molecules is sp. Moreover, nitrogen atom is also attached via triple bond and it also has a lone pair of electrons. Hence, the hybridization of nitrogen atom is also sp.

Thus, we can conclude that s and p type of orbitals overlap to form the sigma bond between C and N in H−C≡N:

Explanation:

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3. 4×106m.

Answers

Answer:

if not sure sorry hope someone helps u❤️

I will give 100 Points, 5-stars, and Brainliest

Direct contact is necessary for which type of energy transfer?

A. Conduction

B. Sound Waves

C. Conduction

D. Convection

Answers

Answer:

Conduction

Explanation:

Because when a molecule is transferred to another molecule then this in going into direct contact

For example if we have a pan and it is boiling well the heat that is on the pan holder that stays in place and it won`t move anywhere else like there is Radiation and Convection but for this question the answer would be Conduction

please help pleaseeeeee

Answers

Answer:

25mg

Explanation:

it basically explains itself

How much would a 70 kg student weigh on Pluto? (massPluto = 1.25 x 1022 kg, radiusPluto = 1.20 x 106 m)

Answers

Answer: the weight would be 4.6 (I think i don’t know))

Explanation:

Can Hotspots can be found at the edges of tectonic plates?

Answers

Answer:

No.

Explanation:

Hot spots don't appear at the barriers of tectonic plates, instead, they originate at hot centres known as mantle plumes. Mantle plumes exist below the tectonic plates and may develop a string of volcanoes on the Earths surface.

Which colour of light is refracted more by a prsim green or blue.explain​

Answers

Answer:

The light waves are refracted as they enter and leave the prism. The shorter the wavelength of the light, the more it is refracted. As a result, red light is refracted the least and violet light is refracted the most - causing the coloured light to spread out to form a spectrum.

Explanation:

hope this helps

Answer: Neither, its actually violet aka purple. This is because it has the shortest wavelength. This is also why red light is refracted the least because it has the longest wavelength.

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What symbols are these?

Answers

Answer:

the bottom one is wollsiegel

calculate the density, in g/l, of sf6 gas at 27°c and 0.500 atm pressure.

Answers

The density of the SF₆ gas at the given pressure and temperature is 2.96 g/l.

The given parameters:

temperature of the SF₆ gas, T = 27 ⁰C = 273 + 27 = 300 Kpressure of the SF₆ gas, P = 0.5 atm

The molecular mass of the SF₆ gas is calculated as follows;

M of SF₆ = 32 + (6 x 19) = 146 g/mol

The density of the SF₆ gas is calculated by applying ideal gas law as follows;

[tex]PV = nRT\\\\PV = \frac{m}{M} RT\\\\PM = \frac{m}{V} RT\\\\PM = \rho RT\\\\\rho = \frac{PM}{RT}[/tex]

where;

[tex]\rho[/tex] is the density of the gasR is the ideal gas constant = 0.0821 L.atm/mol.K

[tex]\rho = \frac{0.5 \times 146}{0.0821 \times 300} \\\\\rho = 2.96 \ g/l[/tex]

Thus, the density of the SF₆ gas at the given pressure and temperature is 2.96 g/l.

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A 5.77 kg object is tied to the end of a cord and whirled in a horizontal circle of radius 355 cm. The object completes 4.4 revolutions every 6.94E-3 hours. What is the centripetal force exerted on the object?

Answers

The centripetal force exerted on the object is 25.24 N.

The given parameters:

mass of the object, m = 5.77 kgradius of the circle, r = 355 cm = 3.55 mnumber of revolutions, N = 4.4 rev for 6.9 x 10⁻³ hours

The angular speed of the object is calculated as follows;

[tex]\omega = \frac{4.4 \ rev}{6.9 \times 10^{-3} \ h} \times \frac{1 \ h}{3600 \ s} \times \frac{2 \ \pi \ rad}{1 \ rev} = 1.11 \ rad/s[/tex]

The centripetal force exerted on the object is calculated as follows;

[tex]F =m \omega ^2 r\\\\F = 5.77 \times (1.11)^2 \times 3.55\\\\F = 25.24 \ N[/tex]

Thus, the centripetal force exerted on the object is 25.24 N.

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Help me quickly! please!!!

A cable pulls a car up a mountain with a force of 4 × 103 N at a vertical constant velocity of 5 m.s-1. It takes 5 minutes to reach the top.

(a)How much work is done in getting the car to the top?
(b)How much work would have been done if the vertical speed was 2,5 m.s-1?
(c)Calculate the power exerted on the cable car in those 5 minutes.

Answers

Answer:

(a) 6,000,000J      

(b)  3,000,000J

(c)  For A 20,000W

But for B 10,000W

The work done in getting  the car to the top is equal to 6 ×10⁶ J. If the vertical speed is 2.5 m/s then, the work done will be  3 ×10⁶ J. The power exerted on the car is in 5 minutes is 20000 J/s.

What is work done ?

In physics, work done is the dot  product of force and displacement. Let w be the work done and F and ds be the force and displacement. Then

W = F.ds

It is given that the, the force of the cable is 4 × 10³ N. The velocity is 5 m/s and time is 5 minutes or 300 seconds. Now, the displacement is the product of time and velocity.

ds = velocity ×  time

    =  300 s ×  5 m/s

    = 1500 m.

Thus the work done = F × ds

                                  = 4 × 10³ N ×  1500 m

                                  = 6 ×10⁶ J .

If the velocity is reduced to half 2.5 m/s , then work done will be reduced to half as 3 ×10⁶ J.

Power is the rate of work done. Thus it is the ratio of work done to time. The power exerted on the car in 5 minutes = 6 ×10⁶ J /300s

                                                                        = 20000 J/s

Hence, the power exerted on the cable car in 5 minutes is 20000 J/s.

To find more on work done, refer here:

https://brainly.com/question/3902440

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density differences in different materials are able to change the _____________ of a wave.

Answers

Answer:

Wavelength and speed both depend on the material of the medium.

Explanation:

Let [tex]f[/tex] denote the frequency of a wave. Let [tex]v[/tex] denote the speed of that wave in a given medium. Let [tex]\lambda[/tex] denote the wavelength of that wave in this medium.

The frequency [tex]f[/tex] of a wave stays the same regardless of the material of the media. However, the speed [tex]v[/tex] of a wave indeed depends on the material of the medium (density of the medium, etc.)

[tex]\lambda = v / f[/tex] and [tex]f[/tex] stays the same regardless of the medium. Thus, the wavelength [tex]\lambda[/tex] of this wave in a given medium would be proportional to the speed [tex]v[/tex] in that medium.

For example, the speed of sound in materials with a larger density (e.g., water) is generally larger than that in materials with lower density (e.g., air.)

When a sound wave travels from air into water, the frequency [tex]f[/tex] of this wave would stay the same. However, since the speed [tex]v[/tex] of the wave would increase, the wavelength [tex]\lambda[/tex] of this wave would also increase.

What would be the extension of the spring for a 3 N weight if the extension of the spring was 4 mm for a 50 g mass?
А 4 mm B)8 mm C)12mm D)24 mm​

Answers

Answer:

24mm

Explanation:

3 N to g is 305.9 g

50g ---- 4 mm

305.9 ----- 4×305.9/50 = 24 mm

A car starts from rest, then accelerates at 1.20 m/s2 for 7.00 s. It hits the brakes,
slowing to a stop at a rate of -4.25 m/s2.
What is the total distance travelled?

Answers

Answer:

the answer is 4.15 m/s2

Explanation:

4.15 m/s2

A champion weight lifter raises a 240 kg barbell a distance of 2.1 m. How much potential energy has

the barbell gained?

Answers

Answer:

Your answer is below …….

Explanation:

25. Brutus, a champion weightlifter, raises

240 kg of weights a distance of 2.35 m.

a. How much work is done by Brutus

lifting the weights?

W=Fd=mgd

= (240 kg)(9.80 m/s2)(2.35 m)

= 5.5 x 103j

b. How much work is done by Brutus

holding the weights above his head?

d=0, so no work

c. How much work is done by Brutus

lowering them back to the ground?

d is opposite of motion in part a, so

W is also the opposite, -5.5 x 103 J.

d. Does Brutus do work if he lets go of

the weights and they fall back to the

ground?

No. He exerts no force, so he does

no work, positive or negative.

If Brutus completes the lift in 2.5 s.

how much power is developed?

* = multiply

[tex]P = \frac{W}{t} = \frac{5.53 * 10x^{3} J}{2.5s} = 2.2 kW[/tex]

_____________________________________

(Hope this helps can I pls have brainlist (crown)☺️)

A boy pushes a stationary box of mass 20 kg with a force of 50 N.
Calculate the acceleration of the box. (Assume that there is no friction.)

Answers

Answer:

2.5m/s^2

Explanation:

Since there is no friction, the only force acting on the box is the applied force

We can now use the equation Fnet = ma

and we can rearrange for a

a = Fnet/m

now input the values

a = 50N/20kg

a = 2.5 m/s^2

If 40 N force is exerted by a box covering 2 metre square area, calculate pressure.

Answers

Force=40NArea=2m^2

[tex]\\ \sf\longmapsto Pressure=\dfrac{Force}{Area}[/tex]

[tex]\\ \sf\longmapsto Pressure=\dfrac{40}{2}[/tex]

[tex]\\ \sf\longmapsto Pressure=20Pa[/tex]

[tex] \sf \huge \red {\dag} Given[/tex]

[tex]\sf \longmapsto \: Force \: = 40 \: Newtons[/tex]

[tex]\sf \longmapsto \: Area \: = \: 2m \: Square \: ( {2m}^{2} )[/tex]

We know that the formula of Pressure is

[tex]\sf \longmapsto \: Force/Area[/tex]

Let's start.

Put the values

[tex]\sf \longmapsto \: \: P = 40 \: newtons(force)/2(Area)[/tex]

[tex]\sf \longmapsto Pressure \: 20 \: N/m^2[/tex]

[tex]\boxed{\sf\red{\boxed{ \sf Pressure ≈ \: 20 \: N/m^2}}}[/tex]

a uniform metre rule of mass 100g balances at the 40cm mark when a mass X is placed at the 10cm mark what is the value of x.pls help I don't know how to solve it​

Answers

Answer:

The fulcrum of the metre stick is at the 40 cm mark

100 g * 10 cm = 1000 g-cm clockwise torque

x * 30 cm = 1000 gm-cm = counterclockwise torque for balance

X = 1000 / (40 -10) = 1000 / 30 = 33.3 gm  at 10 cm to balance

A space ship, initially traveling at a speed of 1,265 m/s, begins to accelerate at a rate of 16
m/s/s. Find the speed of the space ship after it accelerates for 41 s ?

Answers

Answer:

I Think the answer is 1380

Explanation:

Answer: press the link

Explanation:

Please help :[ Hold a flat piece of paper horizontally. Lift it high in front of you, and drop it. Then crumple a piece of paper into a tight ball, hold it high in front of you, and drop it from the same height. Compare the motion of the two pieces of paper.

Answers

The one you lifted in front of you ( the flat piece of paper being holded horizontally ) goes down so slow. While the one being crumpled into a ball goes down fast. Subscribe to DreamfanBG for support.

Answer:

Answer below

Explanation:

The flat piece of paper just gently glided to the ground, as if it were a feather. It didn’t go down in a straight line, it swayed from side to side. The crumpled piece of paper seemed like it had more weight to it (although I know that it didn’t), and it fell way quicker than the flat piece of paper.

_____________________________________________________

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ECONOMIC Q‼️
Which of these is a common concern of an economist ?

A-The distributions of populations and earths resources
B-How people have organized the rules and laws of their societies
C-The cultural habits and social customs of societies
D-How well resources are used by a society

Answers

Answer:

D-How well resources are used by a society

Explanation:

Most economists are concerned with practical applications of economic policy in a particular area, such as finance, labor, agriculture, transportation...

Hope this helps luvv :)

During a ______ Moon phase, the side of the Moon facing Earth isn't reflecting any sunlight from the Sun.
A: Full

B: New

Answers

Answer:

B) New

During a new Moon phase, the side of the Moon facing Earth isn't reflecting any sunlight from the Sun.

Help plz????????? Giving out Brainly

Answers

Answer:

Answer should be (B)

Explanation:

If the forces on an object are balanced (or if there are no forces acting on it), this is what happens: a stationary object stays still. a moving object continues to move at the same speed and in the same direction.

ALSO: forces acting upon an object are balanced, then the object will maintain its state of motion. To maintain the state of motion is to keep the current speed and direction. But if the forces are not balanced, the object will change its state of motion.

What happens when you want to move the boat forward? You pull the oars toward yourself.Explain why you do this.

Answers

Answer:

You pull on the oars. By the third law, the oars push back on your hands, but that’s irrelevant to the motion of the boat. The other end of each oar (the blade) pushes against the water. By the third law, the water pushes back on the oars, pushing the boat forward.

Sheeeeeeeeeeeeeeeeeeeeeeeeeeeeesh

Why are people so rude???

Answers

Answer:

It could be low self-esteem

Explanation:

There probably insecure have problems and issues of their own could be that were abused growing up and weren’t treated right who knows.

Which state of matter has molecules that move the most?

liquid

solid

gas

They are all the same.

Answers

Answer:

gas

Explanation:

in gaseous state molecules move the most because force of attraction between atoms are least in gaseous state

A girl pushes her little brother on his sled with a force of 300 N for 750 m.

Answers

Please find attached photograph for your answer.

Hope it helps.

Do comment if you have any query.

When waves are closer together, the distance between them is _________, therefore the waves have __________ wavelength.

Answers

Answer:

less' shorter

Explanation:

be cuase science

Answer:

The answer is D.

Explanation:

When waves are closer together, the distance between them is less, therefore the waves have longer wavelength.

Se lanza un balón verticalmente hacia arriba con una velocidad de 72 km/h. ¿Qué altura recorrió dicho cuerpo después de 0.05 minutos? (g = 10m/s2)

Answers

Usando la información contenida en la pregunta, la distancia que recorre la bola hacia arriba es de 15 m.

Velocidad inicial = 20 m / s

Tiempo= 3 s

Aceleración por gravedad =  10 ms-2

Velocidad final = 0 m / s

Usando la ecuación;

h = u t - 1 / 2 g t 2

h = (20 × 3) - 1/2 × 10 × (3) ^ 2

h = 60 - 45

h = 15 m

Más información: https://brainly.com/question/6284546

Of the Three elements listed, which element is NOT present in the mixture?

Element D
Element A
Element Z

Answers

Answer:

element ammmkkkv was a very good

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