A car accelerates in the +x direction from rest with a constant acceleration of a1 = 1.51 m/s2 for t1 = 20 s. At that point the driver notices a tree limb that has fallen on the road and brakes hard for t2 = 5 s with a constant acceleration of a2 = -5.03 m/s2. Write an expression for the car's speed just before braking.

Answers

Answer 1

Answer:

v =  1.51t and v = 30.2 m/s just before braking

Explanation:

Using v = u + at where u = initial velocity of car = 0 m/s (since it starts from rest), a = a1 = acceleration before braking = 1.51 m/s², t = t1 = time before braking = 20s and v = speed of car before braking.

Substituting the values of the variables into the equation, we have

v = u + at

v = 0 m/s + 1.51 m/s²t

v =  1.51t and its value after 20 s is

v = 1.51 × 20

v = 30.2 m/s which is the value just before braking.


Related Questions

Do not understand, need help doing this

Answers

Answer:

I found it would be quadrupled if it was doubled

Explanation:

The kinetic energy of an object is the energy possessed by the object due to its motion. It is given by:

where

m is the mass of the object

v is its speed

From the equation, we notice that the kinetic energy is:

Directly proportional to the mass

Proportional to the square of the speed

In this problem, the initial kinetic energy of the object is

K = 100 J

Later, the speed of the object is doubled:

v' = 2v

Therefore, the new kinetic energy will be

So, we see that the kinetic energy will quadruple.

What is the weight of an object a mass of 90.0kg?

Answers

Explanation:

it would be 198.4

you're welcoms

Which diagram best represents the field around a positively charged particle?

Answers

The last one. Opposites attract while similar ones repulse each other so all forces are pushing them apart

An object accelerates at 8 m/s^2 when a force of 40 Newtons is
applied to it. What is the mass of the object? (Use formula: m=Fla)

Answers

Answer:

5 kg

Explanation:

Acceleration = 8 m/s^2

Force = 40 N

Force = mass * acceleration

mass = force / acceleration

mass = 40 / 8

mass = 5 kg

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you have to match the letters in the picture to the list of energy types

Answers

Answer:

you have to match the letters in the picture to the list of energy types

Which of the following is an example of physical change?
A. Mixing baking soda and vinegar together, and this causes bubbles and foam.
B. A glass cup falls from the counter and shatters on the ground.
C. Lighting a piece of paper on fire and the paper burns up and leaves ashes.
D. Baking a birthday cake for your mother.

Answers

The answer is B. Bubbles, foam, burning, and baking are all chemical changes. All the other options changed the substance into something new. The glass cup that shattered is still glass.

B. A glass cup falls from the counter and shatters on the ground.

What is a physical change?  

A physical change is a change in which no new substance is formed after the change occurs

When a glass cup falls to ground , no new substance is formed, hence this change is a physical change

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if you poured oil and water into a beaker , which liquid would be on top and which would be on the bottom ? How would the densities of the liquids compare with their positions in the beaker ? Explain

Answers

Answer:

 oil floats in water due to the fact that it is less dense. since the water is more dense, it is basically heavier, and heavier items always sink, while lighter items float, the same can be said about liquids. denser liquids will sink while less dense items will float.

The three main types of nuclear radiation are alpha, beta, and gamma
Which of the following lists these types of radiation from highest penetrating power to lowest penetrating power?
beta, alpha, gamma
beta, gamma, alpha
ОООО
O gamma, beta, alpha
O alpha, gamma, beta

Answers

Answer:

Gamma, beta, alpha

Explanation:

Gamma rays have the shortest wavelengths of all electromagnetic radiation, has the greatest penetrating power. Gamma rays can pass completely through the human body; as they pass through, they can cause ionizations that damage tissue and DNA. Then Beta particles are more penetrating than alpha particles, but can be stopped by a thin sheet of aluminum.

The correct order of these types of radiation from highest penetrating power to lowest penetrating power is gamma, beta, and alpha. The correct option is C.

Among gamma, beta, and alpha radiation, gamma radiation has the shortest wavelength. This is because gamma radiation consists of high-energy electromagnetic waves, similar to X-rays and light, but with even shorter wavelengths.

In terms of other properties:

Alpha radiation consists of particles called alpha particles, which are helium nuclei (two protons and two neutrons) that are emitted from the nucleus of an atom during radioactive decay. Alpha particles are relatively large and heavy, and they have a positive charge. They have a short range in air and can be stopped by a piece of paper or human skin, but they can cause significant damage to living tissue if they are inhaled or ingested.

Beta radiation consists of particles called beta particles, which are high-energy electrons or positrons that are emitted from the nucleus of an atom during radioactive decay. Beta particles are smaller and lighter than alpha particles, and they have a negative charge. They have a longer range in air than alpha particles, but they can be stopped by a thin sheet of metal or plastic.

Gamma radiation, as mentioned earlier, consists of high-energy electromagnetic waves. Gamma rays are similar to X-rays but have even higher energies and shorter wavelengths. Gamma rays have the longest range in air and require dense materials, such as lead or concrete, to stop them. Gamma radiation is the most penetrating of the three types of radiation and can cause damage to living tissue if exposure is prolonged.

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calculate the acceleration due to gravity on the International Space Station (which orbits at a distance of 408,000 m)

Answers

Answer:

none

Explanation:

none cause it's in space

pls help i’ll give brainliest if you give a correct answer!!

Answers

Answer:

Friction force is the correct answer.

Actually I'm wrong the person who has commented is correct

A motorcycle cop, parked at the side of a highway reading a magazine, is passed by a woman in a red Ferrari 308 GTS doing 120.0 km/h. After a few attempts to get his cycle started, the officer roars off 2.00 s later. At what average rate must he accelerate if 159 km/h is his top speed and he is to catch her just at the state line 3.04 km away?

Answers

Answer:

XZXDHF

Explanation:ZDHF

hii please help i’ll give brainliest if you give a correct answer please please hurry it’s timed

Answers

Answer:

A

Explanation:

You can rule out c and d since they make no sense but i would say a makes more since than b since your sitting on the chair your putting force on it

How does a winter jacket keep you warm while a cold winter day and Why .
Please help me

Answers

In colder weather, people usually wear coats when going outside. Coats keep us warm because of the material of the coat. Our body supplies the heat, and the material helps to trap body heat and keeps the heat from escaping into the air. This is what keeps us warm.

A roller coaster car is at the top of a 65.0 m Crest. If the roller coaster car has 987000 J of potential energy what is its mass

Answers

Pe=M*g*h
M=Pe/(g*h)
M=987000/(9.807*65)
M= 157.8872 KG

HOW MANY SIGNIFICANT FIGURES ARE THERE IN THE NUMBER 405,000?

Answers

Answer:

Three, but see below.

Explanation:

You can be certain of three, but that may not be true at all. The only way to know for certain is to put it into scientific notation.

4.05 * 10^5 would be three, but other answers are possible. For example

4.050 * 10^5 would have 4.


Which of the boxes on the electromagnetic spectra shown below contains all
the frequencies within the visible range?

Answers

Answer:

C.

Explanation:

C. has the box on the colors, which is the rainbow because it is the visible light we are able to see.

Answer:C

Explanation:

1. If two objects each with the mass of 2.0 x 10^2 kg, produce gravitational force between
them of 3.7 x 10^-6N , What is the distance between them ?

Answers

Answer:

r = 0.849 m

Explanation:

Given that,

The masses of two objects, [tex]m_1=m_2=2\times 10^2\ kg[/tex]

The force between the objects, [tex]F=3.7\times 10^{-6}\ N[/tex]

We need to find the distance between the masses. The force between two objects is given by the relation as follows :

[tex]F=G\dfrac{m_1m_2}{r^2}[/tex]

r is the distance between them

[tex]r=\sqrt{\dfrac{Gm_1m_2}{F}} \\\\r=\sqrt{\dfrac{6.67\times 10^{-11}\times (2\times 10^2)^2}{3.7\times 10^{-6}}} \\\\r=0.849\ m[/tex]

So, the distance between them is 0.849 m.

What is the wavelength of these waves?
pls help ​

Answers

Wavelength is the distance between one point of a wave to the same point of the next wave. So the answer is 6 meters.
Please add me as a brainliest.
6 meters it says it right there

A projectile is sitting on top of a cliff that is 250m above ground. The projectile is
launched with a horizontal speed of 25m/s

(a) How far from the base of the cliff did the projectile “land?”

(b) What is the vertical speed of the projectile when it lands [just before it hits
the ground]?

(c) How long did it take the projectile to reach the ground?

Answers

a. 178.5 m

b. 69.97 m/s

c. 7.14 s

Further explanation

Given

height = 250 m

vox = 25 m/s

Required

distance from base

vertical speed(vy)

time to reach ground

Solution

voy = 0

h=voy.t + 1/2 gt²

h = 1/2gt²

250 = 1/2.9.8 t²

t=7.14 s

x = vox.t

x = 25 x 7.14

x = 178.5 m

vy = voy + gt(voy=0)

vy = 9.8 x 7.14

vy = 69.97 m/s

Please help with this question !!!!!

Answers

Answer:

te puedo ayudar pero corazón y estrella

y ando buscando novia por si quieres ser mia

An example of a single displacement reaction is

Answers

Answer:

CL2+H2O----------->2HCL+[0]

A 2-kg mass placed 30-cm to the left of the fulcrum is balanced by a 2-kg mass placed ______ cm to the right of the fulcrum.

Answers

Answer:

30 cm

Explanation:

0.06 or  [tex]\frac{1}{15}[/tex]

What is the effort and load arm?

The lever has two “arms”:

The load arm is the portion of the lever directly connected to the load.

The effort arm is the portion of the lever to which we apply the effort, or input force.

The formula of the mechanical advantage(MA) of a lever is given as

MA = load/effort.

Given,

load = 2kg , effort = 30cm

MA = [tex]\frac{2}{30}[/tex] = [tex]\frac{1}{15}[/tex]

MA  = 0.06 cm

Therefore,

A 2-kg mass placed 30-cm to the left of the fulcrum is balanced by a 2-kg mass placed  0.06 cm to the right of the fulcrum.

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Help me plz. I'll mark brainiest

Answers

Answer:

I'm pretty sure question one is D. Anatomy and physiology

Explanation:

normally you'd have to learn about Physiology before you move on to therapy from my knowledge...

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Which of the following statements about transition metals is true?
a.
They are never found uncombined in nature.
b.
They include familiar metals such as gold, silver, copper, and nickel.
c.
They are so soft that they can be cut with an ordinary knife.
d.
They are the most reactive of all the types of metals.

Answers

Answer:

b.They include familiar metals such as gold, silver, copper, and nickel.

They include familiar metals such as gold, silver, copper, and nickel.

Transition metals are like main group metals in many ways: They look like metals, they are malleable and ductile, they conduct heat and electricity, and they form positive ions.

What are metals ?

"A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable or ductile."

What are transition metals ?

"Transition metals are placed between s−block and p−block elements in periodic table. They are termed as d-block elements. These metals are unstable and exhibit transitional behavior between s block and p block elements, hence the name transition metals."

What is electricity ?

"Electricity is defined as the rate of flow of charges in a conductor."

Electricity is defined as the effects of an electric charge. An example of electricity is the force that powers a light bulb. An example of electricity is lightning. An example of electricity is static electricity, the buildup of electric charges on an object's surface.

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Three forces are acting on an object as shown in the diagram. The object is not moving. Two forces are to newtons and 10 N. Third force is:

Answers

The object is not moving, so the net force acting on it is zero.

The two given forces act in the same direction with a total magnitude of 2 N + 10 N = 12 N.

The third force acts counter to these with some magnitude F to give a net force of 0, so that by Newton's second law

F = 12 N

In order to generate electricity from mechanical energy, one essential element needed to
transform the energy into electrical energy is
A.an insulator
B.a magnet or a magnetic field
C. a plastic sphere
D. a light bulb

Answers

B: q magnet or a magnetic field

What is the speed of a runner that runs 400m in 48.42 seconds?

Answers

Answer:

The speed is that it would take 121.05 seconds to run a kilometer.

Explanation:

Since there are 1000 meters in a kilometer, divide 400 meters by 4, and 48.42 by 4. Then you get 100 meters equals 12.105 seconds. Multiply that by ten, and you get 121.05 seconds

what is the acceleration of an object if the object has an initial speed of 230 m/s and speeds up to 650 m/s. The time it takes for this to happen is 30 seconds

Answers

Answer:

explain this

Explanation:

Which method of popcorn popping transfers heat into the kernels without any direct
contact (nothing hot touched the kernels)? Explain.
Which method of popcorn popping requires the kernels to move through the heat source
in order to pop. Explain.
Describe another example of an object being heated through conduction.

Answers

Answer:

you plug in and turn on the popper, and then the hot air begins to rise in the popper while cooler air falls. As hot air circulates past the popcorn kernels and so the kernels absorb the hear

what are the standard units of displacement?

Answers

the answer is meters....I think??
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