In 1993, Ileana Salvador of Italy walked 3.0 km in under 12.0 min. Suppose that during 115 m of her walk Salvador is observed to steadily increase her speed from 4.20 m/s to 5.00 m/s. How long does this increase in speed take?

Answers

Answer 1

Answer:

t = 25 seconds

Explanation:

Given that,

Distance, d = 115 m

Initial speed, u = 4.2 m/s

Final speed, v = 5 m/s

We need to find the time taken in increasing the speed.

We know that,

Acceleration, [tex]a=\dfrac{v-u}{t}[/tex] ....(1)

The third equation of kinematics is as follows :

[tex]v^2-u^2=2ad\\\\\text{Put the value of a in above equation}\\\\v^2-u^2=2\times \dfrac{v-u}{t}\times d\\\\\because (a^2-b^2)=(a-b)(a+b)\\\\(v-u)(v+u)=\dfrac{2\times (v-u)d}{t}\\\\t=\dfrac{2d}{v+u}\\\\\text{Putting all the values}\\\\t=\dfrac{2\times 115}{4.2+5}\\\\t=25\ s[/tex]

Hence, it will take 25 seconds to increase the speed.


Related Questions

it takes 1.4 minutes for Jonny to get to class which is a distance of 82 meters away s. what is Johnny’s average speed in seconds?

Answers

We have to use the equation speed=distance/time.
We want the average speed in second so we have to change the minutes into seconds. We can do this by multiplying the minutes by 60 (60seconds in 1 minute). 60x1.4= 84 seconds.
Speed=distance/time, distance is 82 and time is 84 so speed=82/84
Average speed = 0.98ms^-1 (2dp)

A race car accelerates from 0 m/s to 20.0 m/s with a displacement of 35.0 m. What is the vehicle's acceleration?

a 5.7 m/s2
b .84 m/s2
c 6.1 m/s2
d .29 m/s2

Answers

Explanation:

Using Equations of Motion :

[tex] {v}^{2} = {u}^{2} + 2as[/tex]

[tex]a = \frac{{v}^{2} - {u}^{2}}{2s} = \frac{400 - 0}{70} = 5.71msec^{ - 2} [/tex]

One way to decrease acceleration is to
a. increase mass
b. decrease mass
c. decrease force and mass equally
d. increase force more than mass

Answers

To decrease acceleration is to increase mass and to increase acceleration u have to decrease ur mass

function of alcohol in alcohol thermometer​

Answers

Alcohol is increasingly expanding with heat. Having it go up the ladder quicker than a lot of liquids would have done. It has a low freezing point, too. It's easy to dye because of the readability. I 'm sure someone will teach you about the evaporative effects of alcohol, and why they do these things. Though that's why it's used briefly in thermometers.

Answer:

Fahrenheit's first thermometer contained alcohol, which has a lower freezing point than water. ... Glass bulb thermometers work because liquids, such as water, alcohol, or mercury, expand slightly when the temperature rises. If the liquid is trapped in a narrow tube, it has nowhere to go but up. I think this may help you

What is the average of 255, 242, 245?

Answers

Answer:

The average is 247.33 if it is for the whole number then it is 247

Explanation:

I did it by adding it all together and dividing it by 3

Answer:

247.33 is the average.

Explanation:

To find the average of a set of numbers:

a. add them up.

b. divide by how many numbers there are.

SO:

a. 255 + 242 + 245 = 742.

b. 742 (total) divided by 3 (# of numbers) = 742/3 = 247.33.

Hope this helps!


A car reversing at -7.2 m/s has a displacement of -21.6 m. How long did this take?

Answers

Answer:

Time=distance/velocity

T=S/V

T=(-21.6)/(-7.2)

Time=3seconds

Martin Luther King, Jr., was awarded the Noble Peace Prize * Yes No

Answers

martin luther jr was awarded the nobel peace prize

Answer

Explanation:

duh he was fighting for peace half of his life

Which ball has the greater acceleration at the instant of release?
Ball thrown upward or downward

Answers

They're equal.

Ignoring air resistance, any object you're not holding onto has the same, constant acceleration ... 9.8 m/s^2 down ... from the moment it leaves your hand until the moment it hits the ground.

It doesn't matter how heavy the object is, and it doesn't matter whether you throw it up, down, or sideways, or just let go and let it drop.

The graph shows the motion of a lift starting at rest and initially moving upwards: What is the acceleration of the lift between 0 and A?

Answers

Answer:

0.67 m/s²

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 0 m/s

Final velocity (v) = 2 m/s

Time (t) = 3 secs

Acceleration (a) =?

Acceleration can be defined as the rate of change of velocity with time. It can be represented mathematically as:

Acceleration = change in velocity /time.

a = (v – u) /t

With the above formula, we can calculate the acceleration of the lift as shown below:

Initial velocity (u) = 0 m/s

Final velocity (v) = 2 m/s

Time (t) = 3 secs

Acceleration (a) =?

a = (v – u) /t

a = (2 – 0) /3

a = 2/3

a = 0.67 m/s²

Thus, the acceleration of the lift between 0 and A is 0.67 m/s².

An advertising balloon shaped like a giant soda can is 15 feet tall and 7 feet wide. How many cubic feet of helium will be needed to fully inflate the balloon?

Answers

Answer:

576.975 cubic feet of helium will be needed to fully inflate the balloon

Explanation:

To determine how many cubic feet of helium will be needed to fully inflate the balloon, we will determine the volume of the balloon.

From the question,

The balloon is shaped like a giant soda can.

A giant soda can is cylindrical.

Hence, we can determine the volume of the balloon shaped like a giant soda can by using the formula for finding the volume of a cylinder.

The formula for finding the volume of a cylinder is

V = πr²h

Where V is the volume of the cylinder

π is a constant (Take π = 3.14)

r is the radius of the cylinder

and h is the height of the cylinder

From the question, the balloon is 15 feet tall and 7 feet wide

Hence,

Height, h = 15 feet

Width = 7 feet

(NOTE: The width of a cylinder is the same as the diameter)

Then, diameter = 7 feet

Radius, r is given by

Radius = Diameter / 2

Then, Radius = 7 feet / 2 = 3.5 feet

∴ Radius, r = 3.5 feet

Now, for the volume of the balloon,

V = πr²h

V = 3.14 × (3.5)² × 15

V = 3.14 × 12.25 × 15

V = 576.975 cubic feet

This is the volume of the balloon.

Hence, 576.975 cubic feet of helium will be needed to fully inflate the balloon.

What did Belgium do to the congo?​

Answers

Answer:

They killed 10 million people and registered it as a colony

Explanation:

Brainliest helps


1. How should Rick correct his technique?
2. Are these students behaving appropriately? If not, what should they
be doing differently?
the guy on the left is rick , the girl in the middle is sarah, and the guy on the right is Andrew.

Answers

Answer:

1) Rick should be taking and gathering the gas with his hand towards his face gently to get just a whiff.

2) These students are doing the complete opposite of what should properly be done. Andrew shouldn't be drinking any chemicals that don't belong in his body. Sarah shouldn't be throwing whatever chemicals into a mixture, this can cause a lot of possible danger. Rick shouldn't be directly smelling the gas which can also be harmful. Rick needs to be wearing gloves and smell the gas in a proper way. Sarah should wear goggles and pay attention to what she is mixing. Andrew should be wearing gloves and goggles and shouldn't be drinking the chemical.

A 1-kg mass is dropped from a third floor window. The acceleration of the mass is found to be 8 m/s2. What is the average force of air resistance? A) 1.8 N B) 7 N C) 8 N D) 9.8 N

Answers

Summary:
m=1kg
a=8 m/s^2
g= 9,8 m/s^2
F(ar)=?


I hope to help you

Physical Science is the study of

Answers

Answer:

Physical science is the study of the inorganic world. That is, it does not study living things. (Those are studied in biological, or life, science.) The four main branches of physical science are astronomy, physics, chemistry, and the Earth sciences, which include meteorology and geology.

Explanation:

Physical science is the study of the inorganic world. That is, it does not study living things

what does it mean to be a base physical quantity​

Answers

Answer:

Hello! :)

Explanation:

A base quantity (or basic quantity) is chosen and arbitrarily defined, rather than being derived from a combination of other physical quantities. The 7 base quantities are: SI units are used as standardised units in all measurements in the world. SI is the short form for “International System of Units”

Hope This Helps!!!

how many significant figures are in the number 347,000​

Answers

Answer:

there are 3 significant figures.

Explanation:

significant figures are 3,4,7.

What is the acceleration of a 2,000 kg truck if it takes a 5,500 N force to move it forward?

Answers

Explanation:

Newton's second law:

F = ma

5500 N = (2000 kg) a

a = 2.75 m/s²

John has decided he needs to work harder on his Social Studies project. Then, his teacher says if he gets a good grade in Social Studies, he may be eligible for a special scholarship for college. What type of motivation is present here?
a.
Intrinsic
c.
Extrinsic to intrinsic
b.
Extrinsic
d.
Intrinsic to extrinsic



Please select the best answer from the choices provided


A
B
C
D

Answers

Answer: Extrinsic to intrinsic

Explanation:

The type of motivation is present here is d. Intrinsic to extrinsic

The following information should be considered:

Intrinsic motivation comprise of performing a task since it's personally rewarding to you. While on the other hand, Extrinsic motivation comprise of finishing a task since of outside causes like avoiding punishment or collecting a reward.

Learn more: https://brainly.com/question/1152162?referrer=searchResults

hey can anyone help me out in dis

Answers

Answer:

A) moving randomly

B) collide into each other

D) high kinetic energy

Explanation:

Gas particles move very fast (high kinetic energy) and in unpredictable directions (moving randomly). They also collide into each other.

I hope this helps!  If it does, a Thanks or brainliest would be much appreciated :)

Uncle Fester's CD's

Congratulations, your uncle fester has just willed you his CD collection!!! Using what you know about classification, see if you can arrange these CDs into similar groups to make them easier for your customers to find. Make a list of four groups that these CDs can be classified into.

The rest of the graph looks like this but here are the CD's for group 3 and Group 4.

Group 3
The Beatles
Beyonce
Alicia Keys
Carrie Underwood

Group 4
Bach
Blake Shelton
Beach Boys
Post Malone


I am having trouble with the graph.​

Answers

Answer: hey

Explanation:

Determine the skater's average velocity from t= os to t= 16s. (average velocity is the displacement (final position minus initial position) divided by time elapsed.)

Answers

Answer:

v = 0.5 m/s

Explanation:

The attached figure shows Robin's positions wrt time who is rollerskating down a marked side walk.

We need to find the skater's average velocity from t= os to t= 16s.

Average velocity = displacement/time

Displacement = final postion - initial position

Displacement = (8 - 0) m/s

Displacement = 8 m/s

Time, t = (16 - 0) s

So,

[tex]v=\dfrac{(8-0)\ m}{(16-0)\ s}\\\\v=0.5\ m/s[/tex]

So, the skater's average velocity from t= os to t= 16s is 0.5 m/s.

Convert 540 cg= ____ Hg

Answers

540 centigram is 0.054 hectograms

Which accident will be more damaging, collision between two trucks

moving with a speed 50 km/hr or collision between two cars moving with a speed of 50 km/hr? Explain.

Answers

Answer:

collision between truck

Explanation:

Answer. Collision between trucks, because more is the mass, more is the inertia and therefore more is the momentum. Mass of the trucks is more than that of cars so collision of trucks will cause more damage.

It is collision truck because the more is the mass, more is the inertia and therefore more is the momentum. Mass of the trucks is more than that of cars so collision of trucks will cause more damage.

20 POINTS! ANSWER CORRECTLY FOR BRAINLIEST!

Which of these is a similarity between a polar and a subtropical jet stream?
A. Both are formed at latitudes close to the poles.
B. Both are formed at latitudes close to the equator.
C. Both are formed at the boundary of warm and cool air masses.

(D not included because I know for a fact it is incorrect, I honestly think the answer is C but I just want other peoples opinions)

Answers

Answer:

C, Both are formed at the boundary of warm and cool air masses.

Answer:

c

Explanation:

a car drives at 88 km/h over a distance of 22 kilometers calculate in minutes the time taken for the audi to travel this distance

Answers

V=88 km/h d=22km t=? if d/t=V t=d/V t=22km/88km/h

t=0,25h

t=1500min

i hope this helps

What is the IMA of the following pulley system?

Answers

The IMA of pulley system can be defined as the ratio of output force to input force.

And IMA stands for Ideal Mechanical advantage

Answer:

5

Explanation:

Which of the following is a common ground water contaminant
A.ozone
B.nuclear waste
C.carbon monoxide
D.fertilizers

Answers

The answer to the question is D:Fertilizers

household chores are a good way to fit exercise into your everyday ruotine

Answers

True, but is that your question?

Answer:TRUE

Explanation:

It’s counts as moving around so yes exercise

A farmer wants to determine which of two brands of cow feed is best for the cows on a farm. Before using one of the feeds on all the cows, the farmer decides to conduct an experiment using 36 individual cows. Which of the two plans for randomly assigning the treatments should the farmer use? Explain. (4 points) Plan A: Choose the 18 cows that are lowest in weight. Feed Brand K to all 18 of those cows. Feed Brand L to the remaining 18 cows. Plan B: Choose 18 of the 36 cows at random. Feed Brand K to those 18 cows and Brand L to the remaining 18 cows. Plan B, because the sample of cows is randomly chosen Plan A, because the cows that are lowest in weight need the feed the most and should be treated first Plans A and B are equivalent because they both follow experimental design. Plans A and B are both poorly designed because there are not enough cows to test. The plans cannot be evaluated from the information given.

Answers

Answer:

Plan B, because the sample of cows is randomly chosen

A ball, initially at rest, reaches a speed of 20 m/s at the bottom of the apparatus. If it takes the ball 10 seconds to reach the bottom, what is the ball’s average acceleration?

Answers

Answer:

2 m/s²

Explanation:

Given:

v₀ = 0 m/s

v = 20 m/s

t = 10 s

Find: a

a = (v − v₀) / t

a = (20 m/s − 0 m/s) / 10 s

a = 2 m/s²

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