A car is moving at a speed of 72 km / h on a horizontal section. What is the braking distance of the car if the friction force is equal to the size of the weight of the car? (20 m) (+ formula)

Answers

Answer 1

Answer:

20.4m

Explanation:

72kmhr(1000mkm)(hr3600sec)=20ms  

Use principles of conservation of energy.

The initial kinetic energy of the car is equal to the work done by friction during braking:

KE=Wfric  

12mv2=(Ffric)d  

but the force of friction = weight of the car = mg

12mv2=mgd  

mass cancels in both terms, which tells us the answer is independent of mass

12v2=gd  

12202=(9.81)d  

d=20.4m  

Note that the correct answer should actually be 20. m with only 2 significant figure accuracy since 72 km/hr only has 2 sig fig accuracy.


Related Questions

The brightest light detected from the star Antares has a frequency of about 3 x 10^(14) Hz. What is the wavelength of this light?

Answers

Taking into account the definition of wavelength, frecuency and propagation speed, the wavelength of a light with a frequency of 3×10¹⁴ Hz is 1×10⁻⁶ m.

First of all, wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

On the other side, frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).

Finally, the propagation speed is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave disturbance propagates along its displacement.

The propagation speed relate the wavelength (λ) and the frequency (f) inversely proportional using the following equation:

v = f * λ

All electromagnetic waves propagate in a vacuum at a constant speed of 3x 10⁸ m/s, the speed of light.

In this case, you know:

v=3x 10⁸ m/s f= 3×10¹⁴ Hz λ= ?

Replacing:

3x 10⁸ m/s= 3×10¹⁴Hz× λ

Solving:

λ= 3x 10⁸ m/s ÷ 3×10¹⁴Hz

λ=1×10⁻⁶ m

In summary, the wavelength of a light with a frequency of 3×10¹⁴ Hz is 1×10⁻⁶ m.

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PLEASE ANSWER ASAP
A 5 kg bowling ball traveling at 2 m/s hits a motionless 10 kg bowling ball. If the smaller ball bounces back at a speed of -1 m/s, what will be the speed of the larger ball after the collision?

Answers

Hi there!

Recall the conservation of momentum:

m1v1 + m2v2 = m1v1' + m2v2'

Let m1 = 5 kg ball and m2 = 10 kg ball

Since m2 is at rest, we can rewrite:

m1v1 = m1v1' + m2v2'

Plug in the given values:

5(2) = 5(-1) + 10v2'

Solve for v2':

10 = -5 + 10v2'

15 = 10v2'

15/10 = 1.5 m/s

Given ↷

m1 =5kgm2=10( since it's at rest)v1=2m/sv2=0(since it's at rest)v1' = -1To find ↷the speed of the larger ball after the collisionSolution↷

We know that,

m1v1 + m2v2 = m1v1' + m2v2'

5 x 2 + 0 = 5 x -1 + 10 x v2'

10= -5 +10 x v2'

15 = 10 x v2'

v2' = 15/10

v2' = 1.5 m/s

hence , the speed of the larger ball after the collision will 1.5m/s



Which statements represent properties of intermolecular forces? Select all that apply.

1. As the temperature decreases, the kinetic energy of the particles increases, and the molecules will move more. This causes the

Intermolecular forces to decrease.

2. As the kinetic energy of the particles increase, the Intermolecular forces decrease. 3.As the distance between the particles decreases, the intermolecular forces Increase.

4. As the kinetic energy of the particles increase, the Intermolecular forces Increase.

Answers

Answer:

Two numbers

Explanation:

see it first

....................................

Answers

Answer:

yeah

Explanation:

Helllo, hope you are doing well :)

if there is a gravitational force between all objects, why do we not feel or observe it?

Answers

We do not feel the gravitational forces from objects other than the Earth because they are weak.

Answer:

We do. It's just way too small compared to the force between the objects we're observing and the earth. It's like looking inside a room with an elephant and a grain of rice. The rice is there, it's just too small compared to the room and the elephant inside for you to notice it. Or, if you ever traveled on a plane, you can easily see the towns, or the roads, but not the single people walking the street.

A 22 kg body is moving through space in the positive direction of an x axis with a speed of 190 m/s when, due to an internal explosion, it breaks into three parts. One part, with a mass of 13 kg, moves away from the point of explosion with a speed of 130 m/s in the positive y direction. A second part, with a mass of 2.2 kg, moves in the negative x direction with a speed of 460 m/s. What are the (a) x-component and (b) y-component of the velocity of the third part

Answers

Answer:   Our notation is as follows : the mass of the original body is M=20.0kg ; its initial velocity is  

ν

 

0

=(200m/s)  

i

^

 ; the mass of one fragment is m  

1

=10.0kg ; its velocity is  

ν

 

1

=(100m/s)  

j

^

 ; the mass of the second fragment is m  

2

=4.0kg ; its velocity is  

ν

 

2

=(−500m/s)  

i

^

 ; and , the mass of the third fragment is m  

3

=6.00kg . Conservation of linear momentum requires  

          M  

ν

 

0

=m  

1

 

ν

 

1

m  

2

 

ν

 

2

+m  

3

 

ν

 

3

 .  

The energy released in the explosion is equal to ΔK , the change in kinetic energy .  

(a) Using the above momentum -conservation equation leads to  

             

ν

 

3

=  

m  

3

 

M  

ν

 

0

−m  

1

 

ν

 

1

−m  

2

 

ν

 

2

 

 

             =  

6.00kg

(20.0kg)(200m/s)  

i

^

−(10.0kg)(100m/s)  

j

^

−(4.0kg)(−500m/s)  

i

^

 

 

          =(1.00×10  

3

m/s)  

i

^

−(0.167×10  

3

m/s)  

j

^

.  

The magnitude of  

ν

 

3

 is  

                        ν  

3

=  

(1000m/s)  

2

+(−167m/s)  

2

 

=1.01×10  

3

m/s  

It points at θ=tan  

−1

(−167/1000)=−9.48  

 (that is at 9.5  

 measured clockwise from the +x axis) .  

(b) The energy released is ΔK :  

             ΔK=K  

f

−K  

i

=(  

2

1

m  

1

ν  

1

2

+  

2

1

m  

2

ν  

2

2

+  

2

1

m  

3

ν  

3

2

)−  

2

1

Mν  

0

2

=3.23×10  

6

J

Explanation:

a dragster accelerate to a speed of 112m/s over a distance of 398m/s. determine the acceleration (assume uniform) of the dragster

Answers

457 is the absolute correct answer I got my teacher to help hope this helps

An object weights 1000N on the earth’s surface. [ g=10N/Kg]
Calculate its mass

Answers

Answer: An object weights 1000N on the earth's surface. ... Calculate its mass ... strength is 10 N/kg how many newtons does a 30kg object weigh.

Explanation:


1 Loudness and pitch are two important properties of a musical sound.
a If a musician plays a softer note, which property has been changed,
loudness or pitch?
b If the musician makes the note lower, which property has been
changed, loudness or pitch?

Answers

pitch loudness is with you lower you tone & get quite

Please help...
Will give the brainliest !!!
Please answer correctly

Answers

5) a) An alpha particle consists of 4 nucleons. Two of these are protons and two are neutrons.  An alpha particle carries a charge of +2 (due to the particles having 2 protons).

b)  A beta minus particle is a fast moving electron that's emitted from the nucleus. It's created when neutrons in the nucleus decays to form a proton & the beta particle.

c) A 3rd type of ionising radiation has no mass. It's called gamma radiation (gamma rays / X - rays). This type of radiation is a type of wave with a very short / low wavelength.  (shortest wavelength among others)

d) Gamma radiation is a part of the electromagnetic spectrum.

_______

Hope it helps ⚜

Plzzzz help meeeeee plzzz

Answers

hun I wish I can help you but I have the same problem here!! sorry

where would you look for the youngest stars in the milky way galaxy?

Answers

Answer:

at the center of the galaxy

Explanation:

as there r more new born stars found

A helicopter travelling at a velocity of 15 m/s [W] accelerates uniformly at a rate of 7.0 m/s2 [E] for 4.0 s. What is the helicopter’s final velocity?

Answers

If we take West to be the negative direction, then the initial velocity is -15 m/s and the acceleration (which points East) is +7.0 m/s².

After t = 4.0 s, the helicopter's velocity is

-15 m/s + (7.0 m/s²) (4.0 s) = +13 m/s

or 13 m/s [E].

Please find attached photograph for your answer.

Hope it helps.

Do comment if you have any query.

Question 2

You can make the puck travel in complex ways by placing a set of charges around on the field. So, here’s your game challenge:
Arrange sources charge around to propel the puck from its starting position into the goal. That’s pretty easy for a straight shot; you just put a negative charge behind the goal. But what if there are barriers along the way? This is a real test of your physical understanding, including Newton’s laws of motion and electrostatic forces. Game’s on!

Part A

On the control bar, check the Trace and Field boxes. The game has three Difficulty levels. Start with Difficulty level one and arrange source charges to get the puck into the goal. Once you’ve made a score at any level, increase the Difficulty level. Take a screen capture of two of your most difficult goals and paste them here. At least one of these should be at Difficulty level 2 or 3.

Answers

Answer:

A. The electric field lines point outward and the black puck moves backwards. From this I can see that I can't put the red charge in front of the black puck because it will go away from the goal.

B. The electric field lines point inward and the black puck moves forwards and backwards. The conclusion I made from this was the blue charge by itself will not be able to get into the goal.

C.The puck moves faster when the mass increases and moves slower when the mass decreases. The more mass, the more force that is applied to the puck.

D.  The relationship between the speed of the black puck and its distance from the blue charge is when the puck is further away from the blue charge, the slower the puck moves away from it.

Explanation:

Brainlest if this helped!

A circular coil consisting of 500 turns with an area of 6.0x10-4 m 2 is rotating in a uniform magnetic field. At the start, the normal to the coil is perpendicular to the magnetic field. After 15s, the normal to the coil is 60⸰ with the magnetic field. The average induced emf is -0.058V. What is the magnitude of the magnetic field?

Answers

The magnitude of the magnetic field in the coil is 21.65 T.

The given parameters;

number of turns, N = 500 turnsarea of the coil, A = [tex]6\times 10^{-4} \ m^2[/tex]change in time, t = 15 s

The induced emf in the coil is determined by applying Faradays law;

[tex]emf =N \frac{d\phi }{dt} \\\\emf = N ( \frac{\phi _2 - \phi_1}{t} )\\\\emf= N(\frac{BAsin\ 60 - BAsin\ 90}{t} )\\\\emf = NBA(\frac{sin60 - sn90}{t} )\\\\-0.058 = 500(6\times 10^{-4})\times B\times (\frac{0.866 - 1}{15} )\\\\-0.058 = -0.00268B\\\\B = \frac{0.058}{0.00268} \\\\B = 21.65 \ T[/tex]

Thus, the magnitude of the magnetic field in the coil is 21.65 T.

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Thirty Joules of energy are transferred out of a system. The energy is lost through heat, mechanical, and electrical energy. If mechanical energy took up 10 J and electrical energy took up 5 J, how many Joules were lost through heat energy?

OPTIONS

5 J



15 J



30 J



45 J

Answers

Answer:

its 15 J i belive

Explanation:

Which is true of the intensity of sound?

Answers

Answer:

c.

Explanation:

A particle has 37.5 joules of kinetic energy and 12.5 joules of gravitational potential
energy at one point during its fall from a tree to the ground. An instant before striking
the ground, how much mechanical energy.

Answers

Hi there!

[tex]\large\boxed{ME = 50 J}}[/tex]

Mechanical Energy = Potential Energy + Kinetic Energy, or:

E = U + K

Plug in the given potential and kinetic energies:

E = 12.5 + 37.5 = 50 J

2. In a race, if a runner starts and stops at the same position, what is their
displacement? *

Answers

Answer:

It is the same

Explanation:

I Jsut know

Calculate the relative molecular of calcium carbonate

* as following method*

Answers

Answer:

100.22

Explanation:

Have a great day!

The gravitational field strength on Mars is 3. 7 N/kg. Kai has a mass of 55 kg. What would Kai weigh on Mars? Give your answer to 1 decimal place.

Answers

Hi there!

Weight = mass × acceleration due to gravity (or gravitational field strength)

We can write this as:

W = mg

Plug in the given values:

W = 55 × 3.7

W = 203.5 N

An amateur astronomer has just discovered a dwarf planet in an orbit past Pluto. Choose the best unit of measure to describe how far out in the solar system it is from the Sun.

Answers

the answer is B) Light years

why does the energy of characteristic x rays tend to increase for heavier elements?

Answers

The energy of characteristic x rays tend to increase for heavier elements

because the charge of the nucleus increases.

X ray is a form of an electromagnetic spectrum and the energy is directly

proportional to the charge of the nucleus. This implies that an increase in

the nucleus charge will lead to a corresponding increase in x ray energy

and vice versa.

X rays energy is also usually more in heavier elements than when

compared to lighter elements

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22.13 .. Two very long uniform lines of charge are parallel and are separated by 0.300 m. Each line of charge has charge per unit length 5.20 mC>m. What magnitude of force does one line of charge exert o

Answers

Answer:

Two very long uniform lines of charge are parallel and are separated by 0.300 m. Each line of charge has charge per unit length.

Explanation:

Asap

A cyclist needs to spin 100 meters with a velocity of 5 m/s. How long will the cyclist take?

Answers

Answer:

[tex]v = \frac{d}{t} \rightarrow t= \frac{v}{d} \\ = 100m \div 5m. {s}^{ - 1} = \frac{100}{5} \\ \color{green} \boxed{ t = 20s}[/tex]

Describe what introspection is.

Answers

Answer:

Introspection is a process that involves looking inward to examine one's own thoughts and emotions. ... The experimental use of introspection is similar to what you might do when you analyze your own thoughts and feelings but in a much more structured and rigorous way.

Explanation:

Example of it: The definition of introspection is self-examination, analyzing yourself, looking at your own personality and actions, and considering your own motivations. An example of introspection is when you meditate to try to understand your feelings. noun.

Answer:   Introspection is when you examine your own thoughts, feelings, and emotions. A spiritual idea of introspection is like examining your soul while a pyschological way would be examining your mental state.

Explanation:  tried my best

Glucose typically enters the cell through which mechanisms

Answers

Answer:

facilitated diffusion

A person drops two objects from the same height. One object weighs 15 N, and the other weighs 10 N. How does the mass of the objects relate to the force of gravity on them? A. The 10 N object has the same mass as the 15 N object. B. The 10 N object has more mass than the 15 N object. C. The 15 N object has twice the mass of the 10 N object. D. The 15 N object has more mass than the 10 N object. SUR​

Answers

Answer:

Your answer would be D :)

Explanation:

An object with a higher mass will always fall faster due to gravity acting upon it. 15 N is more massive than the 10 N object, so statement D is correct.

If two stars are in a binary system with a combined mass of 5.5 solar masses and an orbital period of 12 years, what is the average distance between the two stars

Answers

The average distance between the two stars is 792 light years

Let the mass of the first star be [tex]m_1[/tex]

Let the mass of the second star be [tex]m_2[/tex]

The combined mass of the two stars, [tex]m_1+m_2=5.5[/tex] solar masses

The orbital period of the stars, P = 12 years

Average distance between the two stars, D = ?

The average distance between the two stars can be calculated using Kepler's equation

[tex]D=(m_1+m_2)P^2[/tex]

Substitute [tex]m_1+m_2=5.5[/tex] and P = 12 into the formula [tex]D=(m_1+m_2)P^2[/tex]

[tex]D=5.5(12^2)[/tex]

D = 5.5(144)

D = 792 light years

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A ball is launched from a slingshot. As the ball travels along its trajectory, what force(s) are acting on it? Select all that apply.
Group of answer choices

Answers

Force of air and gravitational force are acting on the ball when launched from the slingshot.

When a ball is launched from a slingshot, during its travel force of air as well as gravitational force are acting on the ball because there is air which moves opposite to the motion of a ball whereas the force of gravity attracts the ball downward.

The force of air slows down the motion of the ball while on the other hand, the force of gravity brings the ball to the ground due to attraction. If these two forces are not present then the ball continues its motion forever so we can conclude that force of air and force of gravity are acting on the ball when launched from the slingshot.

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