a) A car accelerates uniformly at 3.7 m s⁻² as it passes a stationary road train. The initial speed of the car is 30 m s⁻¹, and it reaches the speed limit of 130 km h⁻¹ as it passes the front of the cab. Calculate the length of the road train. Give your answer to 3 significant figures. include units in your answer.
b) The braking distance of a road train travelling at 15 m s⁻¹ is 70 m. Assuming that the same deceleration is applied at all speeds, calculate the braking distance of a road train travelling at 25 m s⁻¹

Answers

Answer 1

(a) The length of the train is 54.6 m

(b)  The braking distance of the road train is 194.44 m

The given parameters:

acceleration of the car, a = 3.7 m/s²

initial velocity of the car, u = 30 m/s

final velocity of the car, v = 130 km/h = 36.11 m/s

To find:

the length of the train

The length of the train is the distance travelled by the car

The distance traveled by the car is calculated as:

[tex]v^2 = u^2 + 2as\\\\2as = v^2 - u^2\\\\s = \frac{ v^2 - u^2}{2a} \\\\where;\\\\s \ is \ the \ distance \ travelled \ by \ the \ car\\\\s = \frac{(36.11)^2 - (30)^2}{2\times 3.7} \\\\s = 54.585 \ m\\\\s \approx 54.6 \ m[/tex]

Thus, the length of the train is 54.6 m

(b) The braking distance of a road train travelling at 25 m s⁻¹

[tex]a = \frac{v_1^2}{2s_1} = \frac{v_2^2}{2s_2} \\\\Given;\\\\s_1 = 70 \ m\\\\v_1 = 15 \ m/s\\\\v_2 = 25 \ m/s\\\\s_2 = ?\\\\2s_2v_1^2 = 2s_1v_2^2\\\\s_2 = \frac{ 2s_1v_2^2}{2v_1^2} \\\\s_2 = \frac{s_1v_2^2}{v_1^2} \\\\s_2 = \frac{70\times 25^2}{15^2} \\\\s_2 = 194.44 \ m[/tex]

Thus, the braking distance of the road train is 194.44 m

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Related Questions

a heat engine gives out 400J of heat energy as the useful work.calculate the energy given to it as input if its efficiency is 40%?​

Answers

Answer:

E(efficiency) = E(out) / E(in)

.4 = 400 J / E (in)

E (in) = 1000 J

Heat input : 1000J

What is efficiency of a heat engine ?

The efficiency of a heat engine  is defined as the ratio of work done by the heat engine absorbed per cycle.

Given : work output = 400 J

          Efficiency = 40 % = 0.4

          heat input = ?

Efficiency = work output / heat input

                0.4 = 400/heat input  

heat input : 1000J

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Which elements are in the same column (above or beneath) oxygen?

Answers

Answer:

Bismuth And Nitrogen

Explanation:

Because they have the same number of Valence Electrons

Answer:

There is nothing above oxygen but beneath there is sulfur as shown in the figure.

What is the relationship between the number of resistors ,the effective resistance of the circuit and the total current in parallel

Answers

Answer:

As more and more resistors are added in parallel to a circuit, the equivalent resistance of the circuit decreases and the total current of the circuit increases. Adding more resistors in parallel is equivalent to providing more branches through which charge can flow.

what is displacement

Answers

Answer:

finding the volume of an irregular shape

Is the earth flat or round or a donut?

Answers

The earth is obviously round.

4. A sprinter begins from rest and accelerates at the rate of 2 m/s2 for 200 m.
a) What is the sprinter's velocity at the end of the 200 m?
b) How long does it take him to cover it?
c) What is his average velocity?

Answers

Answer:

v=28.28m/s t=14.14s average velocity =2m/s

Explanation:

Starting at rest the initial velocity is 0 substituting that in the first equation of motion v=u+atgives the final velocity but we first have to determine the time using the third equation of motion which is s=ut+1/2at^2 and then do the substitution. Average velocity is the determined by adding the initial and final velocity then divide it by 2

if a body covers a distance of 25m in a straight line in 5sec ,calculate the averge velocity of the body​

Answers

solution,

Displacement (s)=25m

Time taken (t)=5 sec

Average Velocity (v)= ?

now,

v= d÷ t

v= 25m÷ 5

v= 5m/s

Answer:

[tex]displacement= 25m \\ time = 5 \: sec \\ avarage \: velocity = \frac{displacement}{time} \\ = \frac{25}{5} = 5 \frac{m}{sec} \\ thank \: you[/tex]

A ball rolled at a speed of 3m/s for 2.5s. How far did it travel?

Answers

Answer:

7.5 m

Explanation:

speed = distance/time

=> speed × time = distance

=> (3 m/s) × (2.5 s) = distance

=> 7.5 m = distance

slove these question​

Answers

Answer:

the answer would be left side a to right side b left side b to left side c left side c to left side d left side d to right side e

Explanation:

state the factors that affect tha gravitational force​

Answers

Explanation:

1. Mass of an object

2. Distance between the objects

Answer:

When dealing with the force of gravity between two objects, there are only two things that are important – mass, and distance. The force of gravity depends directly upon the masses of the two objects, and inversely on the square of the distance between them.

Explanation:

PLEASE let me know you are satisfied with my answer or not

Any two waves that meet as they travel through the same medium will interact. If the two waves are in phase their crests will coincide and they will experience _____ interference, producing a wave with a(n) _____ amplitude.

Answers

Answer:

constructive

alpitude

12. A measuring cylinder has 150ml. of water in it. When a stone is immersed into the measuring cylinder, the water level raised to 210cm. What is the volume of the stone?​

Answers

Answer:

60ml

Explanation:

I'm going to assume you mean 210ml not centimeters. To find the volume all we do is subtract both values or with the formula [ f - i = v ]  where f = final amount and i = initial amount.

210 - 150 = 60ml

Best of Luck!

Correction:

The final level of water should be = 210

[tex] {cm}^{3} [/tex]

or 210 ml

━━━━━━━━━━━━━

Given:.Initial level of water = 150mlFinal level of water = 210 ml

━━━━━━━━━━━━━

Need to find:Volume of stone =?

━━━━━━━━━━━━━

Solution:

The volume of stone will be equal to the change in level of water.

that's,

210 - 150 [tex] {cm}^{3} [/tex]

= 60[tex] {cm}^{3} [/tex]

Hence the volume of the stone is 60 [tex] {cm}^{3} [/tex]

What is the name given to a celestial object with a known brightness, used to establish distances in astronomy?

Answers

Parallax is an important rung in the cosmic distance ladder. By measuring the distances to a number of nearby stars, astronomers have been able to establish relationships between a star's color and its intrinsic brightness, i.e., the brightness it would appear to be if viewed from a standard distance.

Round 0.010229 to four sig figs

Answers

It would be 0.01023.

0.010229 has 5 sig. fig.'s (leading zeros do not count)

So rounding to 4 sig. fig.'s is just a matter of rounding off the last digit, which leaves you with 0.01023.

what colors are included in our visible spectrum?​

Answers

ALL colors are in the visible spectrum.

"Color" is a word we use to describe light that our eyes can detect.  If the light has a "color", that means we can see it, and somebody gave it a name.  If we can't see it, then we don't have a "color" to describe it.

Every color that has ever been perceived by human eyes is present in the humanly-visible spectrum, except "black".

There are at least hundreds of them. Probably thousands.  Maybe millions.

The Colours that are included in visible spectrum are - 7 Colours namely :

Red Orange yellowgreen blueindigoviolet

Explanation:

when white light passes through a prism , the violet light bends most and the red light bends the least.Dispersion of light is the phenomenon of splitting of white light into its constituent seven colours on passing through a glass prism.The band of seven Colours so obtained is called visible spectrum.

The seven Colours of white light are Violet, indigo , blue, green , yellow, orange and red . It is remembered by the acronym - VIBGYOR.

The acceleration of a particle is given by a = c1 + c2v, where a is in millimeters per second squared, the velocity v is in millimeters per second, and c1 and c2 are constants. If the particle position and velocity at t = 0 are s0 and v0, respectively, determine expressions for the position s of the particle in terms of the velocity v and time t.

Answers

The expression for the position of the particle in terms of velocity and time is given as, s = vt

The given expression:

[tex]a = c_1 + c_2v[/tex]the unit of a = mm/s²the velocity, v = mm/sc₁ and c₂ are constantthe position of the particle at time, t = 0, is s₀ and v₀

To find:

The expression for the position s of the particle in terms of the velocity v and time t

Determine the value of the constants from second equation of motion given as:

[tex]s = vt + \frac{1}{2}at^2\\\\substitute \ the \ given \ value \ of \ a\\\\s = vt + \frac{1}{2}(c_1 + c_2v)t^2\\\\s = vt + \frac{1}{2} c_1 t^2 + \frac{1}{2} c_2vt^2\\\\divide \ through\ by \ t^2\\\\\frac{s}{t^2} = \frac{v}{t} + \frac{1}{2} c_1 + \frac{1}{2} c_2v\\\\multiply \ through \ by \ 2\\\\\frac{2s}{t^2} = \frac{2v}{t} + c_1 + c_2v\\\\when \ t = 0\\\\0 = 0 +c_1 + c_2v\\\\c_1 + c_2v = 0\\\\from \ the \ original \ equation;\\\\s = vt + \frac{1}{2} (c_1 + c_2v)t^2\\\\[/tex]

[tex]s = vt + \frac{1}{2}(0)^2\\\\s = vt[/tex]

Thus, the expression for the position of the particle in terms of velocity and time is given as, s = vt

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A glacier advances at 8 x 10-6 cm/s.
How far will it move in 6.6 y?
Answer in units of cm

Answers

The glacier with move approximately 1665.1cm after 6.6 years

Physical Science Essential Question: How can the scientific process be used to help us investigate and understand natural phenomena? Elaborate: Challenge students to pretend they are on the scientific journey to develop a vaccine to stop the zombie apocalypse and they need to design an experiment as a result of working in a laboratory. Ask the students to write 2-3 paragraphs describing what they would test and why might this be important in science and the real world. They might need to include the following terms: Experimental design
Test variable
•Outcome
•Control variable
•Hypothesis
•Testable
•Graphs and charts

Answers

Answer:

It C 100% bc i alrweady learn this

BRAINLIEST PLS HELP

Imagine that you tested 20 high school students (15 male, 5 female). Twelve males and four females reported feeling a calming effect after exposure to the color blue.

In two to three sentences, explain what conclusions could be drawn from this information.

Answers

Answer:

Answer:

Explanation:

It means that out of 20 students, 3 males and 1 female were digital screen addicts because they were getting dangerous amount of blue light. Thus couldn't feel calming sensation that a human feels while seeing blue light. The rest students were getting balanced blue light. So they were getting relaxed feeling while being exposed to blue light.

Rearrange the equation below with the required unknown becoming the subject

a. V as subject
b. U as subject
c. a as subject
d. S as subject

Answers

Answer:

a.

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

b.

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

c.

[tex] {v}^{2} = {u}^{2} + 2as \\ 2as = {v}^{2} - {u}^{2} \\ a = \frac{ {v}^{2} - {u}^{2} }{2s} \\ \\ a = \frac{ {v}^{2} }{2s} - \frac{ {u}^{2} }{2s} [/tex]

d.

[tex] {v}^{2} = {u}^{2} + 2as \\ 2as = {v}^{2} - {u}^{2} \\ s= \frac{ {v}^{2} - {u}^{2} }{2a} \\ \\ s = \frac{ {v}^{2} }{2a} - \frac{ {u}^{2} }{2a} [/tex]

I hope I helped you^_^

Activity log - Chest and Back Record your time and activity below and in your unit fitness log. If a particular category does not apply, leave it blank. Date: Warm-up: Cool-down: Type of Activity: (Cardiovascular, Muscular, or Flexibility) Description of Activity and Time: Intensity Level: (Moderate or Vigorous) Total Time:

Answers

Answer:

Muscular and vigorous

Explanation:

Big gains only

Answer:Date: 08/21/21

Warm-up: 5 minutes

Cool-down: 1 minute

Type of Activity: Muscular

Description of Activity and Time: push up, and repetitions 10 minutes

Intensity Level: Moderate

Total Time:16 minutes

Explanation:

How far would a snowmobile travel in 0.5 hours at a rate of 25 km/h?

Answers

Answer:12.5 km

Explanation:

0.5=1/2

25 x 1/2 = 12.5 (25 ÷ 2 = 12.5)

Answer:

12.5 km

Explanation:

Distance = Speed x Time

               = 25 x 0.5

               = 12.5 km

una estación meteorológica informa que hay olas a lo largo de la costa con una separación de 8 segundos. por tanto, la frecuencia de ola es de...​

Answers

Answer:

si

Explanation:

What is Measurement?​

Answers

Answer:

Measurement is a comparison of an unknown quantity with a known fixed quantity of the same kind. The value obtained on measuring a quantity is called its magnitude. Magnitude of a quantity is expressed as numbers in its units.

Explanation:

measurement is necessary to express the amount or rate of any physical quantity

what are the major parts of the ear?​

Answers

Explanation:

1.The parts of the ear include:

External or outer ear, consisting of: Pinna or auricle. This is the outside part of the ear. ...

2.Tympanic membrane (eardrum). The tympanic membrane divides the external ear from the middle ear.

3.Middle ear (tympanic cavity) , consisting of: Ossicles. ...

4.Inner ear , consisting of: Cochlea.

Explanation:

The major parts of ear are:-

1) Outer ear

PinnaExternal auditory canalTympanic membrane

2) Middle ear

MalleusIncusStapes

3) Inner ear

CochleaSemicircular canalsVestibule

en and Karen are travelling for the weekend. They both leave from Jen's house and meet at their destination 250 miles away. Jen drives 45mph the whole way. Karen drives 60mph but leaves a half hour after Jen. How long does it take for Karen to catch up with Jen

Answers

Answer:

1 1/2 hours. for Karen to catch Jen.

Explanation:

Karen needs to make up 22.5 km which is the distance Jen travels in 1/2 hour.

The distance where they meet must be equal from the starting point.

Jen

Jen is out 1/2 hour longer.

Let the Karen's time  = t

d = r * t

d = 45 * (t + 1/2 hour)

Karen

d = 60 * t

The distances are equal

so

Meeting time

45*(t + 1/2 hour) = 60 * t

45t + 22.5 = 60t                   Subtract 45t from both sides

22.5 = 15t                              Divide by 15

t = 22.5 / 15

t = 1 1/2 hours = 1.5 hours.

Now you have to interpret the results.

Remember that Jen has travelled 1/2 hour more than Karen

Her time is 2  hours.

Karen's time is 1.5 hours.

Jen travels 2 hours which is 2 * 45 = 90 miles

Karen travels 1 1/2 hours which is 1.5 * 60 = 90 miles

A soccer ball is kicked horizontally. What is its average speed if its displacement is 21.0 m
after 2.00 s?

Answers

Answer:

Below

Explanation:

You can use this formula to find the average speed/velocity

     speed = displacement / change in time

Plugging our values in....

     speed = 21.0 m / 2.00 s

                = 10.5 m/s

Hope this helps! Best of luck <3

The average speed of a soccer ball is 10.5 m/s.

What is speed?

Speed is defined as the ratio of the distance moved by the object at a particular time. The unit of speed is measured in the meter per second, miles per hour, etc. The speed of an object is a scalar quantity and does not require any direction to represent it. It only requires magnitude to represent it.

Average velocity is defined as the sum of all the distances traveled by an object to the time taken by the object to cover the total distance.

Given that a soccer ball is kicked horizontally. its average speed if its displacement is 21.0 m after 2.00 seconds will be calculated as below:-

Speed = displacement / change in time

Speed = 21.0 m / 2.00 s

Speed = 10.5 m/s

Therefore,  the average speed of a soccer ball is 10.5 m/s.

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Help would be very appreciated :)

Answers

Answer:

c. is the answer i think

Explanation:

Answer:

d. is the the naswer I'm sure with it and not much sure but it would be ryt option

A STONE IS THROWN VERTICALLY UPWARD WITH THE VELOCITY 25/s HOW LONG DOES IT TAKES TO REACH THE MAXIMUM HEIGHT?

Answers

Answer:

time taken to reach maximum height is 2.548 sec and Maximum height is 31.855 m

Explanation:

Initial velocity U= 25 m/s

at maximum height velocity, V= 0 m/s

Let the time taken to reach maximum height be t and maximum height be H.

V= U-gt

so 25-9.81.t=0

therefore t= 25/9.81  = 2.548 sec

Now,

H= Ut-1/2(gt^2)

 =25x2.548-0.5x9.81x(2.548^2)

 =31.855 m

                                              Thank you

what is the value of acdeleration due to gravity on the surface of the moon and on the surface of the eatrh​

Answers

Answer:

Explanation:

moon is 1.6metre per second and earth is 9.8 meters per second square

Have a  nice day bye

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