A car of mass 900 Kg is moving with a velocity of 10 m/s. It is brought to rest at 25 m distance by applying the brakes. Calculate the acceleration. Why is it negative? How much force is required to stop the car?​

Answers

Answer 1

Answer:

Assumption: the acceleration of this vehicle is constant until it comes to a stop.

Acceleration: [tex](-2)\; \rm m\cdot s^{-2}[/tex].

The acceleration of this vehicle is negative because the velocity of this vehicle is decreasing over time.

Explanation:

Let [tex]u[/tex] denote the initial velocity of this vehicle. [tex]u = 10\; \rm m\cdot s^{-1}[/tex].Let [tex]v[/tex] denote the final velocity of this vehicle. [tex]v = 0\; \rm m\cdot s^{-1}[/tex] as the vehicle has come to a stop.Let [tex]x[/tex] denote the displacement of this vehicle. [tex]x = 25\; \rm m[/tex].Let [tex]a[/tex] denote the acceleration of this vehicle. The value of [tex]a\![/tex] needs to be found.

Assume that the acceleration of this vehicle, [tex]a[/tex], is constant. The SUVAT equations would apply.

The time [tex]t[/tex] required for braking is neither given nor required. Hence, make use of the SUVAT equation [tex]v^{2} - u^{2} = 2\, a\, x[/tex] to relate [tex]u[/tex], [tex]v[/tex], [tex]a[/tex], and [tex]x\![/tex].

Rearrange this equation to find an expression for [tex]a[/tex], the acceleration of this vehicle:

[tex]\begin{aligned}a &= \frac{v^{2} - u^{2}}{2\, x} \\ &= \frac{(0\; \rm m\cdot s^{-1})^{2} - (10\; \rm m \cdot s^{-1})^{2}}{2\times (25\; \rm m)} \\ &= \frac{0^{2} - 10^{2}}{2 \times 25}\; \rm m \cdot s^{-2} \\ &= -2\; \rm m\cdot s^{-2}\end{aligned}[/tex].

When the rate of change of a value is greater than [tex]0[/tex], that value would become larger over time.When the rate of change of a value is equal to [tex]0[/tex], that value would be constant.When the rate of change of a value is smaller than [tex]0[/tex], that value would become smaller over time.

Acceleration is the rate at which velocity changes over time.

The velocity of the vehicle in this question is getting smaller over time. Hence, the rate of change of the velocity of this vehicle (that is, the acceleration of this vehicle) would be a negative number.


Related Questions

4.You decide to flip a coin to determine whether to do your physics or English homework first. The coin is flipped
straight up.
a. What is the velocity of the coin at the top of its trajectory?
b. If the coin reaches a high point of 0.25 m above where you released it, what was its initial speed? c. If you
catch it at the same height as you released it, how much time did it spend in the a

Answers

For the coin that is flipped straight up we have:

a. The velocity at the top of its trajectory (at the maximum height) is 0.

b. When it reaches a high point of 0.25 m above where it was released, the initial velocity is 2.21 m/s.

c. The time that the coin spends on the air is 0.44 s.

a. The velocity of the coin at the top of its trajectory is zero because in the maximum height the ball will stop and then will start to move down.

b. When the coin reaches a high point of 0.25 m above where it was released, the initial velocity can be calculated as follows:

[tex] v_{f}^{2} = v_{0}^{2} - 2gh [/tex]

Where:

[tex] v_{f}[/tex]: is the final velocity = 0 (at the maximum height)

[tex] v_{0}[/tex]: is the initial velocity =?

g: is the acceleration due to gravity = 9.81 m/s² (it is negative because its direction is the opposite to the direction of motion of the coin)

h: is the height = 0.25 m

Hence, the initial velocity of the coin is:

[tex] v_{0} = \sqrt{2gh} = \sqrt{2*9.81 m/s^{2}*0.25 m} = 2.21 m/s [/tex]

c. The time that the coin spends on the air is given by the sum of the rise time and the fall time:

Rise time

[tex] t_{s} = -\frac{v_{f} - v_{0}}{g} = -\frac{0 - 2.21 m/s}{9.81 m/s^{2}} = 0.22 s [/tex]

Since the ball is caught at the same height as it was released, the rise time is the same as the fall time, so the total time is:

[tex] t = 0.22 s*2 = 0.44 s [/tex]  

Therefore, the coin spend 0.44 seconds in the air.

You can find another example of initial and final velocity here: https://brainly.com/question/13275688?referrer=searchResults

I hope it helps you!                      

Which of the following statements most accurately differentiates potential and kinetic energy?

A. Kinetic energy is a form of mechanical energy, while gravitational potential energy isn't.
B. Gravitational potential energy is a form of mechanical energy, while kinetic energy isn't.
C. Any object that has motion has potential energy, while any object not in motion but with the potential to do work has kinetic energy.
D. Any object that has motion has kinetic energy, while any object not in motion but with the potential to do work has potential energy.

Answers

Answer:

D) Both parts are true.

Hey there, hope my answer helps :)

Answer: D) Any object that has motion has kinetic energy, while any object not in motion but with the potential to do work has potential energy.

d) All of the
The volume of solid is measured in
a) Litters
b) Grams
c) Cubic centimeters
d) All of the above

Answers

a) Liters ... It COULD be.  The "Liter" is a perfectly good unit of volume, but it's typically used for liquids and gases, not solids.

b) Grams ... definitely NOT.  The "gram" is a unit of mass, not volume.

c) Cubic centimeters ... Yes. This is a unit of volume.

d) All of the above ... No.

The volume of solid is measured in

a) Litters

b) Grams

c) Cubic centimeters

d) All of the above

Humans have been on the Moon, so why haven’t humans visited any other planets in the solar system?

Answers

Answer

Its because of the atmospheric pressure that may crush the humans

Explanation:

2246.7 milliseconds to seconds

Answers

Answer:

2.2467

Explanation:

Divide the value of time by a thousand

An automobile starts at rest and accelerates at 3.5 m/s/s after a traffic light turns green. How far will it have gone when it is traveling at 25 m/s?

Answers

Please find attached photograph for your answer. Please do comment whether it helped you or not

If you want to find out the density of an object, what two things do you need to know about it?

Answers

Answer:

How do I determine density? Density is not something that is directly measured. Typically if you want to know the density of something you will weigh it and then measure its volume.

what do you consider to be your primary loving relationship?​

Answers

Answer:

I do not own this picture inserted below. Credits to the rightful owner. But i hope this help you <3

Cody drives around a track that has a radius of 11460 m at a speed of 36 km/hr.

What distance did he go in one lap? (km)

What was his one lap displacement? (km)

What was his speed in km/hr?

What was his velocity in km/hr?

How long did one lap take him? (hours)

Answers

When is the acceleration of a body is positive negative and zero

According to the law of conservation of matter, we know that the total number of atoms does not change in a chemical reaction and thus mass is conserved. The reactant in this model is hydrogen peroxide. Hydrogen peroxide decomposes to produce water and oxygen gas. How many water molecules must be added to complete this model?

Answers

Answer:

In a chemical reaction the total mass of all the substances taking part in the reaction remains the same. Also, the number of atoms in a reaction remains the same. Mass cannot be created or destroyed in a chemical reaction.

Explanation:

iii A load of 2.5 N is hung on the spring.
1. What does the letter N stand for?
[1]
2. Use the graph to estimate the overall length in mm of the spring when 2.5 N is hanging from it. [2]
[Cambridge IGCSE Physics 0625/22 Question 2, October/November, 2010)

Answers

N stands for Newton
2- upload the graph..

Need help ASAP!!! Need graphs drawn and the answers to the question on top of each table

Answers

Answer:

1) 8s

2).8cm/s/s

3)3.5?

Explanation:

not sure about answer 3 FYI

Define upstroke and downstroke?

Answers

Answer:

The upstroke is a mechanism that helps to raise the plunger and downstroke helps to help lower the plunger. On the up-stroke of the plunger, the lower valve opens and the upper valve is closed. Whereas, on the downstroke, the lower valve closes and the upper one opens.

A bicyclist is traveling at +25m/s when he begins to decelerate at -4m/s2. How fast is he traveling after 5 seconds

Answers

Answer:

+5m/s

Explanation:

When doing the math we figure out that e is going to be slowing down at -4m/s² for 5 seconds. In total he is slowing down -20m/s which we take from the total speed of +25m/s to get his current new speed.

True or false: Venus is the hottest planet

Answers

True. Venus is the hottest planet in the solar system. Venus is the second closest planet to the sun, Mercury is first.

It is easy to cut curry by a sharp knife,why?

Answers

The sharper the knife, the less effort is required to cut the item.

Group 2 elements have two valence electrons. Which kind of bond will they most likely form, and why?(1 point)

A covalent bond is likely because they want to share those two valence electrons in order to become stable.

An ionic bond is likely because they will want to give away two valence electrons in order to become stable.

An ionic bond is likely because they are metals and will want to bond with nonmetals.

A metallic bond is likely because they are metals and can bond with other metals.

Answers

Answer:

An ionic bond is likely because they will want to give away two valence electrons in order to become stable.

Considering the octet rule and the definition of ionic bond,   the correct option is the second option: "An ionic bond is likely because they will want to give away two valence electrons in order to become stable."

Consider first the octet rule, which states that atoms combine or form ions with the goal of obtaining 8 electrons at their last level. In this way, an electronic configuration similar to that of the closest noble gas in the periodic table is reached. This happens because this configuration, of full electronic level, is very stable from the energy point of view

On the other hand, an ionic bond is a type of chemical bond that occurs when one atom gives up an electron to the other, in order for both to achieve electronic stability.

This union normally occurs between metal and nonmetal elements with different electronegativity, which means that the elements have different capacity to attract electrons. In general, metal elements are willing to donate an electron while nonmetals are willing to receive it.

In summary, an ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.

Finally,  the correct option is the second option: "An ionic bond is likely because they will want to give away two valence electrons in order to become stable."

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https://brainly.com/question/12064867?referrer=searchResultshttps://brainly.com/question/5277024?referrer=searchResults

A speed versus time graph is shown:

A Speed versus Time graph is shown with y-axis labeled position in centimeters per second up to 5 and x-axis labeled time in seconds up to 8. A straight line connects the points 0, 0 and 4, 4. A horizontal line connects points 4, 4 and 8, 4.

Which statement accurately describes the motion of the object in the graph above?

Group of answer choices

It is moving from 0 s to 4 s at a constant speed of 2 cm/s.

It is at rest for 4 seconds from 4 s to 8 s and then speeds up.

It is moving from 4 s to 8 s at constant speed of 4 cm/s.

It is speeding up from 0 s to 4 s then it is at rest.

Answers

Answer:

it is moving from 4s to 8s at a constant

speed of 4 cm / s

A person is pushing a book lying on a table. Identify the different forces that act on
the book and hence mark their directions.

Answers

Explanation:

There are two forces acting upon the book. One force - the Earth's gravitational pull - exerts a downward force. The other force - the push of the table on the book (sometimes referred to as a normal force) - pushes upward on the book.

There are mainly 3 forces which acts on a book.

Listed below are the forces and their points:-

Earth's Gravitational force of attraction- Usually, we may not consider or notice this force, but when a book falls, we understand this, because the book falls due to this gravitational force.

Force exerted on book while pushing it- While we push a book, we apply Push Force, due to which the book moves on the pushing it on a table.

Frictional Force- We notice that while pushing a book, it does not continuously move in motion. At a certain distance, this Frictional force increases and therefore, the book comes to a halt.

Location- Opposite of exerted force in all directions

đo cường độ dòng điện bằng dụng cụ gì

Answers

Answer:

Explanation:

Dhdhfhfjjfjffj

Why is the sun considerad as the main source of energy?​

Answers

Answer:

The sun is considered as the main source of energy since it is the source of nearly all the earth's energy. Plants produce food using sunlight, and the food we get from plants and animals also has its primary sunlight source.

Hoped it helps you.

Answer:

It is because it supplies most of our energy that we use today, directly or indirectly. It radiates light and heat or solar energy, which makes it possible to exist life on earth.

The Big Bang theory is closely linked to Hubble's discovery that the universe is expanding, which seems to imply that there was a time in the past when the expansion first began. Nevertheless, the Big Bang theory did not gain widespread acceptance among scientists until the 1960s. Why wasn't expansion alone enough to convince scientists that the Big Bang really happened

Answers

Answer:

Although expansion seems to imply a Big Bang, no other specific predictions of the Big Bang theory were tested and confirmed until the 1960s.  

Explanation:

Answer:

Today, the consensus among scientists, astronomers and cosmologists is that the Universe as we know it was created in a massive explosion that not only created the majority of matter, but the physical laws that govern our ever-expanding cosmos.  This is known as The Big Bang Theory. For almost a century, the term has been bandied about by scholars and non-scholars alike. This should come as no surprise, seeing as how it is the most accepted theory of our origins.

;)

suppose you start with an initial velocity of 10 m/s and have an acceleration of -2m/s. what is your final velocity after 9 seconds?

Answers

Please find attached photograph for your answer. Please do comment whether it is useful or not

Complete the statement below about developing technology responsibly.
To develop technology responsibly, people must evaluate both the ____________ and the____________ consequences of the technology​

Answers

Answer:

Positive & negative

Explanation:

To develop technology responsibly, people must evaluate both the immediate and the long-term consequences of the technology.

This entails considering not only the short-term benefits and potential gains but also the potential risks, ethical implications, and broader societal impacts that the technology may introduce. Responsible development requires a comprehensive analysis of how the technology could affect individuals, communities, economies, and the environment. Striking a balance between innovation and accountability is essential to ensure that the benefits of technology are maximized while minimizing any unintended harm. By thoroughly examining both the immediate and long-term consequences, developers can make informed decisions that prioritize the well-being of all stakeholders and foster a more sustainable technological landscape.

To know more about technological landscape, here

brainly.com/question/34008185

#SPJ3

Please help ???????.......

Answers

Answer:

300,000=3×10^3

.000012=1.2×10^-6

Which option is a microscopic property that helps determine whether or not two substances will dissolve with each other? (1 point)

volume

polarity

molecular mass

state of matter

Answers

Answer:

The answer is polarity

Answer:

B: Polarity

Explanation:

9. A train is moving with the velocity of 45 km Ihro The osives applies brace and the train gets stopped in 6 second. Now, calculate as distance covered by the train before coming to
the rest.​

Answers

((12.5 + 0)/2)(6)
D= 37.5 m
I think it’s 37.5 m
I basically just converted 45 km/h to m/s then used the formula d =( (initial velocity + final velocity)/ 2)(t)

A bus travels 6km east and then 8km south. The magnitude of the bus’s resultant displacement is _ km

Answers

Hey there! Here's your answer:

10 km

Here's why:

The bus's displacement has two components, a number of km and the direction of the final position from the initial position.

The bus's displacement is the hypotenuse of the triangle, 10 km southeast of the initial position.

But southeast is only a rough estimate of the direction.

The tangent of the angle is 6/8 or .75, so the amount of angle to the east of south is 37 degrees.

South (180 degrees) minus 37 degrees is 143 degrees.

The car’s displacement is more accurately called 10 km in a direction of 143 degrees from the initial point.

Have a good day!

Which statement correctly compares the valence electrons for atoms of francium (Fr) and barium (Ba)?

(1 point)

Francium has more valence electrons, and they are in a higher energy level.

Barium has fewer valence electrons, but they are in a higher energy level.

Barium has more valence electrons, and they are in a higher energy level.

Francium has fewer valence electrons, but they are in a higher energy level.

Answers

From the Periodic Table...

Francium is a group 1 Element and Barium is a Group 2 Element

This statement is a giveaway as it already tells you that Barium has more valence electrons than Francium since it has 2 electrons in its Outer shell.

This Eliminates Options A and B

Francium has more electrons than Barium

So It should be at a higher energy level.

The correct statement is Francium has fewer valence electrons, but they are in a higher energy level.

The energy level of an element is the region of space around the nucleus where its electrons are found. This corresponds to the period of the element in the periodic table.

Francium is in period 7 in the periodic table (in energy level 7)Barium is in period 6 in the periodic table (in energy level 6)in the electronic configuration of Francium, the valence electron is in 7s¹in the electronic configuration of Barium, the valence electron is in 6s²

Thus, we can conclude that, Francium has fewer valence electrons, but they are in a higher energy level.

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Read the ruler in millimeters to the correct degree of precision
3.50
3.55
35
35.1

Answers

Answer:

The answer is = 35.1 you can see by zooming.

Answer:

The answer would be 35.1

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