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

Worth 10 points! I will give brainliest!! Please help!!! See picture!

Answers

it contains iron. so it aligns with the magnetic Field lines

Answer:

The last option

Explanation:

The larger the number of charges flowing through the wire, the larger is the ____________ flowing in the wire.

Answers

Answer:

The larger the number of charges flowing through the wire,the larger is the current flowing in the wire.

Explanation:

if the wire is large then large amount of current flows through the circuit.but if the wire is small then a smaller amount of current will pass through.

I hope this helps

Mass is measured in
a) Litters
b) Centimeter
c) Newton
d) Kilogram

Answers

Answer:

d) Kilogram.

Hope it helps you

Mass is measured in

a) Litters

b) Centimeter

c) Newton

d) Kilogram

tides occurs in oceans but not in lakes.why?​

Answers

Answer:

Explanation:

Tides occur in the ocean but nit in lakes because an ocean is a free flowing body of water that can travel a large area of the globe while a lake or pond only covers a small area of the earth so it is not affected by gravity as violently and in turn, prevents the formation of tides.

why is there potential for wind energy in the upper himalayanx​

Answers

Answer:

Favorable sites include the tops of smooth, rounded hills; open plains and water; and mountain gaps that funnel and intensify wind. Wind resources are generally more favorable for electricity generation at higher elevations above the earth's surface

A shift inward of the production possibilities curve signifies that _

A. The demand for the products has increased, so the supply will increase
B. The available resources have increased, so potential production levels will increase
C. The available production resources have decreased, so potential production levels will decrease
D. The demand for the products has decreased so, the supply will decrease

Answers

Answer:

c

Explanation:

A shift inward of the production possibilities curve signifies that: C. The available production resources have decreased, so potential production levels will decrease.

A production possibilities curve (PPC) is also referred to as production possibilities frontier (PPF) and it can be defined as a curve that illustrates the maximum (best) combinations of two (2) products which can be produce in an economy if they both depend on these two (2) main factors;

Fixed technology. Fixed resources.

Basically, the production possibilities curve (PPC) illustrates the maximum combinations of goods that are available with fixed technology and resources.

Furthermore, an inward shift of the production possibilities curve (PPC) signifies that the available resources used for production have decreased, so potential production levels would also decrease.

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a radioactive element has a half-life of 30 days. calculate the mass of the element that remains after 20 days if 100g of the element decays. Also, calculate the decay constant.

Answers

Explanation:

the answer is in the image above

A train is moving with the velocity of 10m/s . It attains an acceleration of 4m/s after 5 sec . find the distance covered by train at that time.

Answers

Jdndbxndbsjanwndnfbdbdjdjd

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

Which statement is true?

A. When a gas condenses to a liquid, it absorbs energy.
B. When water boils, it releases energy.
C. When ice melts, it absorbs energy.
D. When water freezes, it absorbs energy.

Answers

Explanation:

The correct answer is option B

Answer:

C. When ice melts, it absorbs energy.

Explanation:

When ice melts, it is getting hotter by absorbing energy and changes from a solid to a liquid. This is an endothermic reaction.

how many seconds are there in 1 day . solve along with steps​

Answers

One minute has 60 seconds, One hour has 60 minutes and one day has 24 hours. Thus, 80 x 60 x 24 = 86,400 sec

if my answer helps you than mark me as brainliest

Answer:

[tex]thank \: you[/tex]

When is the pressure of the man on the ground more – lying position or standing
position? Explain.

Answers

Hi,

The man on the ground in standing position has more pressure. This is because when he stands, only his legs are in contact with the ground. While lying, his body is more in contact with the ground, therefore, he exerts less pressure.

To the point, a man standing position on the ground had more pressure.

More is the area of contact, less is the pressure efforted.

Thank you...

A box is 300 kg & it covers the area of 150 m2 find the pressure exerted by the box in the ground.​

Answers

Answer:

If we assume that the box is a cube with 150 m² surface area

Area of 1 face = 150 m² / 6 = 25 m²

The box will exert a downward force of

Force = mass * acceleration due to gravity

Force = 300 kg * 9.81 m/s² N

Force = 2943 N

The box exerts a pressure ( force / unit area) = 2943 N / 25 m²

Pressure = 117.7 N/m²

Thank you, if you found this helpful please comment.

If Bert the Bat travels eastward at 40 mph with a tailwind of 6 mph, what is his actual speed?

Answers

Answer:

36 mph.

Explanation:

Now Albert here is using the wind to his advantage but if say there was no wind then he would not have the 6 mph behind him so we subtract 6 from 40 to get 36. hope this helps :)

After the experiment, scientists organize and (blank) the data.

Does anyone know what goes in the blank? Im doing a crossword puzzle and I need help, please. (/w\)

Answers

Answer:

analyze

Explanation:

Two trucks left the warehouse at the same time and drove in
the same direction along a straight road. One truck drove at 68
km/h while the other drove at 57 km/h. Find theirs distance
apart after2 hours.

Answers

Truck a
V = 68km/h
t = 2hours

Distance = speed * time

D = 68 * 2

D = 136km




Truck B

Speed = 57km/h

t = 2 hours

Distance = speed * time

D = 57 * 2

D = 114km


Distance travelled by truck A = 136 km

Distance travelled by truck B = 114km

Distance apart = 136km - 114km = 22km

Hence both the trucks will be 22kms apart.

Hope this helps. Plz let me know if you have any doubts.

10. Numerical problems:

b. A stone is thrown vertically upwards with an initial velocity of 20 m/sec.find the maximum height it reaches and the time taken by it to reach the height. (g = 10 m/s2).

c. A car is moving at a rate of 72 km/hr. How far does the car move when it stops after 4 seconds?

d. A bus starts from rest. If the acceleration is 2 m/s2, find
1. the distance travelled.
2. the velocity after 2 seconds.

e. A stone is thrown vertically upward with the velocity of 25 m/s. How longo it take to reach the maximum height? Also calculate the height.


with process please ​

Answers

Answer:

a)20 m,2s

Explanation:

Given

Initial velocity=20 m /sec

g=10 m/s square

v =0m/s

h =?

t =?

now,

v = U +gt

=v=20 +10t

Or,10t=20

Or,t=20

10

therfore ,2 s.

Again,

h=ut -1 gt square

2

Or, h=20×2-1×10(2)square (multiply and cut )2×5 =10

; 2

Or,40-5×4

therefore , 20m

For question e,

u = 25 ms-1
v = 0 m/s
a = -10m/s^2

We have to find time and distance,

For time,

v = u + at

Which can be rephrased as,

v - u/a = t

t = 0 - 25 / -10

t = 2.5 secs

Hence, the stone takes 2.5 secs to reach the maximum height.

To calculate the maximum height attained by the stone, we have to calculate distance/ displacement .

The formula for calculating distance is,

s = ut + 1/2at^2

s = 25 * 2.5 + 1/2 * -10 * 2.5 * 2.5

s = 62.5 + (- 31.25)

s = 62.5 - 31.25

s = 31.25mts

Hence, the maximum distance travelled by the stone is 31.25 meters.

Hope this helps you. Plz let me know if you have any doubts.

What's Centripetal force................

Answers

Answer:

a force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.

Answer:

A centripetal force is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path.

what do you mean by acceleration of a body 10\s?

Answers

Answer:

it means that the body is moving with acceleration increased of 10m in every second.

in the Newton's Third Law of Motion state three characteristics ​

Answers

Answer:

Newton's third law: If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A. This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself.

11. What is the resolution of this ruler? 6-centimeters​

Answers

six cm - centimeters

Slove these problem physics ​

Answers

Answer:

element name = neon

no of proton = 10

no. if neutron = 9

atomic no. = 10

atomic weight = 20.17179u

it lies in group 18 and period 2

it is nonmetal because it is a noble gas .

hope this helped you ☺️

ОООО
A dog runs from his home & goes 400 m around the block before reaching back home. What is the dog's total distance & displacement?
Distance: 0 m & displacement: 400m
Distance: 400 m & displacement:0m
Distance: Om & displacement:4 m
Distance: 4 m & displacement: Om

Answers

Answer:

A dog runs from his home & goes 400 m around the block before reaching back home. What is the dog's total distance & displacement?

Distance: 400 m & displacement:0m

Explanation:

Option B is the answer.

Hope it helps.

how is light reflected from a prism​

Answers

Answer:

White light entering a prism is bent, or refracted, and the light separates into its constituent wavelengths. Each wavelength of light has a different colour and bends at a different angle. The colours of white light always emerge through a prism in the same order—red, orange, yellow, green, blue, indigo, and violet.

White light entering a prism is bent, or refracted, and the light separates into its constituent wavelengths. Each wavelength of light has a different colour and bends at a different angle. The colours of white light always emerge through a prism in the same order—red, orange, yellow, green, blue, indigo, and violet.

maize is called monocot why?​

Answers

Answer:

Rice, wheat, maize all have one cotyledon in their seed, so they are monocots. Explanation: The monocot plants have a single cotyledon. They have a fibrous root system, leaves in monocots have parallel venation.

Explanation:

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

Answers

Answer:

300,000=3×10^3

.000012=1.2×10^-6

Can aurora be found in other planets?

Answers

Answer:

Yes

Explanation:

Any planet with a sufficiently dense atmosphere that lies in the path of the solar wind will have aurora. It has been discoveres in planets like Jupiter, Saturn, etc.

Answer:

yes

Explanation:

Give an example for each of the following, where the force:
a) changes the direction of a moving object.
b) changes the speed of a moving object.
c) changes the shape and size of an object.
d) stops a moving object.
e) moves a stationary object.

Answers

Explanation:

A cricket player hitting the ball from opposite direction.A footballer kicking ball with more force.Heating of a plastic bottle.Applying brake of a car.rolling a stopped marble on a table.

a).  The gravitational forces between the Earth and the Sun bends the Earth's motion along a curving path instead of a straight line.

b).  The gravitational forces between the Earth and a falling rock make the rock fall faster and faster.

c).  The force of a pressurized stream of hot air makes a balloon get rounder and bigger.

d).  The gravitational forces between the Earth and a rock tossed straight up make the rock go slower and slower, and eventually stop.  (In the next instant,  it starts falling, as described in answer-b.))

e).  The acoustic and emotional force of your mother's voice 15 minutes before the school-bus arrives causes you to turn over, sit up, and start putting on your socks.

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.

No links please, links never work, this is science not physics
Which two claims about cats are most likely to be based on science?

A. Cats are the best animals to keep as pets.
B Whiskers help cats sense distances when hunting prey.
C. Cats spend more time sleeping than most other predators.
D. Seeing a black cat is likely to bring you bad luck.

Answers

Answer:

b and c are the answers

A is an opinion, D is a superstitious belief because they haven’t found Jesus obviously

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