A car is driving 12m/sec, has to stop suddenly because a pedestrian dashes out in front of the car. If the coefficient of kinetic friction between the tires and parking lot is ∪=60

what is the time, after the breaks are applied, before the car comes to a stop? Sketch the velocity time graph for the car's motion from the instant the breaks are applied until the car comes to a stop.

Answers

Answer 1

Answer:

Approximately [tex]2\; \rm s[/tex], assuming that the floor of this parking lot is level, [tex]\mu_{\rm k} = 0.60[/tex], and [tex]g = 9.81\; \rm m\cdot s^{-2}[/tex].

Explanation:

Let [tex]m[/tex] denote the mass of this vehicle. Weight of this vehicle: [tex]m\, g[/tex].

If the floor of this parking lot is level, the normal force on this vehicle would be equal to its weight: [tex]N = m \, g[/tex].

Given that [tex]\mu_{\rm k}[/tex], the kinetic friction between this vehicle and the ground would be consistently [tex]\mu_{\rm k} \, N = \mu_{\rm k} \, m \, g[/tex] until the vehicle comes to a stop.

Assuming that all forces on this vehicle other than friction are balanced. The net force of this vehicle during braking would be [tex](-\mu_{\rm k} \, m \, g)[/tex] (negative because this force is opposite to the direction of the motion.)

By Newton's second law of motion, the acceleration of this vehicle would be:

[tex]\begin{aligned}a &= \frac{F_\text{net}}{m} \\ &= \frac{-\mu_{\rm k} \, m \, g}{m} \\ &= -\mu_{\rm k}\, g \\ &= -0.60 \times 9.81\; \rm m\cdot s^{-2} \\ &= -5.886\; \rm m\cdot s^{-2}\end{aligned}[/tex].

In other words, braking would reduce the velocity of this vehicle by a constant [tex]5.886\; \rm m\cdot s^{-1}[/tex] every second until the vehicle comes to a stop. Calculate the time it would take to reduce the velocity of this vehicle from [tex]v_{0} = 12\; \rm m\cdot s^{-1}[/tex] to [tex]v_{1} = 0\; \rm m\cdot s^{-1}[/tex]:

[tex]\begin{aligned}t &= \frac{v_{1} - v_{0}}{a} \\ &= \frac{0\; \rm m\cdot s^{-1} - 12\; \rm m\cdot s^{-1}}{-5.886\; \rm m \cdot s^{-2}} \\ &\approx 2.0\; \rm s \end{aligned}[/tex].

Acceleration is the slope of the velocity-time graph. Since the acceleration here is constant, the velocity-time graph of this vehicle would be a line with a negative slope.

A Car Is Driving 12m/sec, Has To Stop Suddenly Because A Pedestrian Dashes Out In Front Of The Car. If

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This is two or more elements chemically combined in a fixed ratio.


Example: water, carbon dioxide, sodium chloride

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A compound is a substance that contains two or more elements chemically combined in a fixed proportion. The elements carbon and hydrogen combine to form many different compounds.

what two things make up an ionic bond?

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Answer: An ionic bond requires an anion and a cation

E TRUE OR FALSE: Write the word TRUE if the statement is correct, and FALSE if it is not. (3 points each). Write your answer on a separate sheet of paper. 1. Most EM waves has the same speed. 2. EM waves travel at the speed of 4x108 m/s. 3. Electromagnetic waves are transverse waves consisting of changing electric fields and changing magnetic fields. 4. Electromagnetic waves transfer energy through a vacuum. 5. A wave is a disturbance that transfers energy .what the answer?

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Answer:

TRUE

FALSE

TRUE

TRUE

TRUE

TRUE

Explanation:

1. Most EM waves has the same speed. True

2. EM waves travel at the speed of 4x108 m/s. False

3. Electromagnetic waves are transverse waves consisting of changing electric fields and changing magnetic fields. True

4. Electromagnetic waves transfer energy through a vacuum. True

5. A wave is a disturbance that transfers energy. True

Help pls!

A 3 kg mass is raised a distance of 14 m above the earth by a vertical force of 93 N.
The final kinetic energy of the mass, to 3 significant figures, if it was originally at rest is:

Answers

[tex] \large★·.·´¯`·.·★ {Answer}★·.·´¯`·.·★[/tex]

As we know that Kinetic Energy is the Energy that is possessed by a moving object. and if the object is at rest then it doesn't have velocity therefore there is no kinetic Energy.

In the numerical terms we can express it as : -

[tex] \sf0.00 \: \: joules[/tex]

[tex]꧁  \:  \large \frak{Eternal \:  Being } \: ꧂[/tex]

A. praised
B. scolded
C. rewarded
14. Reicon's parents admonished him for breaking their antique collection,
D. silenced
15. I am an advocate of anti-corruption movement in the country.
D. supporter
C. enemy
DirectioRead the statements below. Using context clues, identify the meaning
A. opponent
B. primer
highlighted words.
16. The hotel abolishes its rice-all-you-can policy to avoid wastage of food.
b. removes
d. proposes
A. continues
17. The country has a very tropical climate where it only has dry and wet
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d. collected
a. new
c. outdated
18. The obsolete books and other references in the library resulted to the
removal in the shelves and inventory.
b. old
19. Beverages, such as juices, milk, beers and sodas, have increased in
,
due to low supply and importation issues.
a. drinks b. food
d. pastas
20. The luxurious life of my cousin in an exclusive subdivision in Ta
makes me inspired to dream and work hard for me to escape this unp
d.
a. ordinary b. fantastic
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Help help me plis po summative test ko po ito plis help me

Answers

Answer:

14. scolded

15. supporter

16. i am not sure but I think it is removes

17. comfortable

18. outdated

19. drink

20. it can be fantastic or wealthy

Answer:

14. Reicon's parents admonished him for breaking their antique collection,

scolded

15. I am an advocate of anti-corruption movement in the country.

supporter

16. The hotel abolishes its rice-all-you-can policy to avoid wastage of food.

it is removes

17. The country has a very tropical climate where it only has dry and wet

seasons similar to other countries in Southeast Asia

comfortable

18. The obsolete books and other references in the library resulted to the

removal in the shelves and inventory.

outdated

19. Beverages, such as juices, milk, beers and sodas, have increased in,due to low supply and importation issues.

drinks

20. The luxurious life of my cousin in an exclusive subdivision in Ta makes me inspired to dream and work hard for me to escape this unp.

fantastic

What is the meaning of eddy currents in electromagnetic series?​

Answers

Answer:

currents which circulate in conductors like swirling eddies in a stream in electromagnetic series....

A solar collector for a hot water system absorbs solar radiation at the rate of 660 W/m^2
. Its collecting area is 3.8m^2 . Cold water at 15degrees enters the collector. What volume of
water per minute at an output temperature of 60 degrees can this collector deliver?

Answers

This question involves the concepts of the law of conservation of energy and specific heat capacity.

This collector can deliver "7.96 x 10⁻⁴ m³/min" of water at an output temperature of 60°C.

According to the law of conservation of energy:

Solar Energy = Energy Required to raise the temperature of the water

Solar Power = Energy Required to raise the temperature of the water

[tex]IA=\frac{mC\Delta T}{t}\\\\\frac{m}{t}=\frac{IA}{C\Delta}[/tex]

where,

[tex]\frac{m}{t}[/tex] = mass flow rate = ?

I = solar radiation = 660 W/m²

A = Area = 3.8 m²

ΔT = change in temperature = 60°C - 15°C = 45°C

C = specific heat capacity = 4200 J/kg.°C

Therefore,

[tex]\frac{m}{t}=\frac{(660\ W/m^2)(3.8\ m^2)}{(4200\ J/kg.^oC)(45^oC)}\\\\\frac{m}{t}=(0.0133\ kg/s)(\frac{60\ s}{1\ min})\\\\\frac{m}{t}=0.796\ kg/min[/tex]

Now, the volume flow rate will be:

[tex]\frac{V}{t}=\frac{(\frac{m}{t})}{(density\ of\ water)}=\frac{(0.796\ kg/min)}{(1000\ kg/m^3)}\\\\\frac{V}{t}=7.96\ x\ 10^{-4}\ m^3/min[/tex]

Learn more about the law of conservation of energy here:

brainly.com/question/20971995?referrer=searchResults

The attached picture explains the law of conservation of energy.

If the voltage across a 5-F capacitor is 2*e^-3
V find the current and the power

Answers

Answer correct in this picture………….

Which item is not a solid-state component?

an integrated circuit
a vacuum tube
a diode
a transistor

Answers

Answer:

a vacuum tube is NOT a solid state component

A magnesium ion has a charge of +2 and an oxygen ion has a charge of –2. What is the chemical formula of the compound made of these ions? (correct answer gets brainliest)

A) Mg2O2
B) MgO
C) MgO2
D) Mg2O

Answers

MgO
the charges cancel out :)

A 5kg mass is pushed with a force of 10N for a distance of 2.5 meters. The work done is​

Answers

W = 25 J

Explanation:

Work done on an object is defined as

[tex]W = Fd = (10\:\text{N})(2.5\:\text{m}) = 25\:\text{J}[/tex]

I need the answer fast for c pleaseeee​

Answers

Answer:

F = - K x for spring     (note that that F here is given in grams, F = m g is correct)

K here is 100 g / cm      for the spring constant

x = -420 g / 100 g/cm = -4.2 cm

The spring would compress 4.2 cm for a total length of 20 - 4.2 = 15.8

d)  to compress the spring 6.8 cm one can see that the load would be 680 g

two billiard balls moving along the same line hit each other head-on. each has a mass of 0.220 kg; one has an initial velocity of 1.84 m/s, the other an initial velocity of 0.530 m/s. if the collision is elastic, what are their final velocities? ignore friction.

Answers

Hi there!

Since the collision is elastic, we must also satisfy the following condition:

Ei = Ef, or:

KEi = KEf

Begin by writing an expression for momentum. (p = mv) Remember that one ball's direction is negative; in this instance, we can let the second ball be moving LEFT.

mv1 + mv2 = mvf1 + mvf2

0.220(1.84) + 0.220(-.530) = 0.220(vf1 + vf2)

0.2882/0.220 = vf1 + vf2

1.31 = vf1 + vf2

Now, we can express this as a conservation of energy:

1/2mv1² + 1/2mv2² = 1/2mvf1² + 1/2mvf2²

Plug in values and simplify:

0.403315 = 1/2m(vf1² + vf2²)

Simplify further:

3.6665 = vf1² + vf2²

Use the equation derived from momentum above and solve for one variable:

vf2 = 1.31 - vf1

Plug in this expression for vf2:

3.6665 = vf1² + (1.31 - vf1)²

Expand:

3.6665 = vf1² + 1.7161 - 2.62vf1 + vf1²

Simplify:

1.9504 = -2.62vf1 + 2vf1²

Solve for vf1 using a graphing calculator:

vf1 = -0.53 m/s or 1.84 m/s; we must figure out which one is correct.

Since v1 is heading to the right initially with a velocity of 1.84 m/s, we know that the ball's velocity could not have stayed the same in both magnitude and direction, so the final velocity must be -0.53 m/s.

Now, we can solve for the velocity of the other ball (initial of 0.53 m/s):

vf2 = 1.31 - (-0.53) = 1.84 m/s.

Now, you could have also made the connection that when two balls of the SAME MASS experience an ELASTIC collision, the velocities are simply "exchanged" from one to another. I just used this more "extensive" method to prove this.

I need your help with this question, it’s my final exam for physics

Answers

Answer:

●Bx=Bcos40

Bx=10 × 0.76

Bx=7.6

●By=Bsin40

By=10×0.64

By=6.4

Hope it will help you.

A flywheel with a diameter of 0.692 m is rotating at an angular speed of 208 rev/min. (a) What is the angular speed of the flywheel in radians per second

Answers

[tex]\omega = 21.8\:\text{rad/s}[/tex]

Explanation:

We know that there are [tex]2\pi[/tex] radians in one revolution and 60 seconds in one minute so we can easily convert the rev/min unit to rad/s using the following conversion factors:

[tex]208\:\dfrac{\text{rev}}{\text{min}}×\dfrac{2\pi\:\text{rad}}{1\:\text{rev}}×\dfrac{1\:\text{min}}{60\:\text{s}}[/tex]

[tex]\;\;\;\;\;=21.8\:\text{rad/s}[/tex]

A 100 N crate is being pulled at a constant velocity by a rope a 30 degrees to the horizontalas depicted in the diagramFind the force of friction Show your work and explain your reasoning in two to sentences

Answers

Answer:

Explanation:

As the velocity is constant, Net force is zero. This means that the friction force must equal the applied force in the horizontal direction.

Ff = Fcosθ

if we had a coefficient of kinetic friction μ, we could quantify the friction force more precisely.

μN = Fcosθ

μ(mg - Fsinθ) = Fcosθ

μmg = Fcosθ + μFsinθ

100μ = F(cos30 + μsin30)

F = 100μ / (cos30 + ½μ)

Ff = 100μcos30 / (cos30 + ½μ)

A 100 N create is being pulled at a constant velocity by a rope a 30 degrees to the horizontal as depicted in the diagram given in question the force of friction Ff = 100μcos30 / (cos30 + ½μ).

What is force?

A force in physics is an effect that has the power to alter an object's motion. An object with mass can change its velocity, or accelerate, as a result of a force. An obvious way to describe force is as a push or a pull. A force is a vector quantity since it has both magnitude and direction.

As the velocity is constant, Net force is zero. This means that the friction force must equal the applied force in the horizontal direction.

Ff = Fcosθ

if we had a coefficient of kinetic friction μ, we could quantify the friction force more precisely.

μN = Fcosθ

μ(mg - Fsinθ) = Fcosθ

μmg = Fcosθ + μFsinθ

100μ = F(cos30 + μsin30)

F = 100μ / (cos30 + ½μ)

Ff = 100μcos30 / (cos30 + ½μ)

the force of friction Ff, is 100μcos30 / (cos30 + ½μ).

To learn more about force refer to the link:

brainly.com/question/13191643

#SPJ5


One of the great challenges of cosmology today is to ---
A
determine the amount of matter in the Universe
B
find intelligent signals emanating from outer space
С
look backward in time to before the Big Bang
D
locate wormholes to help define the structure of the Universe

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Answer:

Steady-state theory, in cosmology, a view that the universe is always expanding but maintaining a constant average density, with matter being continuously created to form new stars and galaxies at the same rate that old ones become unobservable as a consequence of their increasing distance and velocity of recession.

Cosmic inflation is a faster-than-light expansion of the universe that spawned many others. ... Cosmic inflation solves these problems at a stroke. In its earliest instants, the universe expanded faster than light (light's speed limit only applies to things within the universe).

what is the velocity of this graph between points a and b? 0.0m/s 2.5m/s 5.0m/s 6.0m/s?

Answers

Pick C. 5.0m/s it’s the right one

Answer:

Pick c is the right one

Explanation:

5.0m/s

plz answer the question.

Answers

Answer:

A. Determine the equation of constraints

tell types of instruments

Answers

Answer:

Instrument Use

Accelerometer Measures acceleration

Altimeter Measures altitude of an aircraft

Ammeter Measures electric current in ampere

Anemometer Measures wind speed

A 0.50-kg mass is attached to a spring of spring constant 20 N/m along a horizontal, frictionless surface. The object oscillates in simple harmonic motion and has a speed of 1.5 m/s at the equilibrium position. What is the total energy of the system?

Answers

Hi there!

With the work-energy theorem for oscillating springs:

ME = KE + PE

[tex]ME = \frac{1}{2}mv^2 + \frac{1}{2}kx^2[/tex]

Where:

m = mass (kg)

v = velocity (m/s)

k = Spring Constant (N/m)

x = displacement from equilibrium (m)

If the object is at the equilibrium position, there is NO potential energy since:

[tex]\frac{1}{2}k(0^2) = 0 J[/tex]

Thus:

[tex]ME = \frac{1}{2}mv^2[/tex]

Plug in the given values:

[tex]ME = \frac{1}{2}(0.50)(1.5^2) = \boxed{0.5625 \text{ J}}[/tex]

Can anyone help me with question 10 a.

Answers

Answer:

it's ahfdfhhh hhgfdjjjjuyggffdddcff

According to the table what was the hikers total displacement the graph has 4km 6km 4km 6km

Answers

Answer:

0

Explanation:

0 is the answer

Water has higher specific heat than aluminum. This is all what you should know to answer following questions. An aluminum rod of mass 1 kg at temperature of 80^0C is placed into 1l of water of temperature 10^0C . there is no heat exchange with surroundings. Which material experiences greater change in temperature while system is reaching the thermal equilibrium

Answers

Answer:

The Aluminum

Explanation:

With a larger specific heat, water requires more heat to raise its temperature by a temperature degree.

In this system, with equal masses of water and aluminum, the heat moving from the aluminum lowering its temperature by one degree is not sufficient to raise the water temperature by one degree.

Nikolai is using a hand-operated grain mill to grind wheatberries into flour. The mill is operated by spinning a fly-wheel with radiusR= 23 cm, which has a handle attachedto the outer edge. After grinding for a few minutes at a con-stant angular speedωi, he lets go of the handle and allows themechanism to come to rest as it undergoes constant angularacceleration. This happens over the course oft= 0.50 s, andthe flywheel undergoes a quarter of a rotation during this time.What is the linear tangential accelerationaof the handle as itcomes to rest? For the limits check, investigate what happenstoaas the time required to stop the flywheel becomes small(t→0).

Answers

Answer:

Explanation:

α = Δω/t = (0 - ωi)/0.50 = -2ωi rad/s²

ωf² = ωi² + 2αθ

θ = (ωf² - ωi²) / 2α

2π/4 = (0² - ωi²) / (2(-2ωi))

2π/4 = ωi / 4

ωi = 2π rad/s

α = -2(2π) = -4π rad/s²

a = rα = 0.23(-4π) = 0.92π m/s² ≈ -2.89 m/s²

as the time to stop approaches zero, acceleration goes toward infinity.

A car travelling at 79.3 Km/h on a highway has 4.22x10 5 J of kinetic energy.

a. What is the mass of the car?

b. If brakes are applied with a force of 2100 N, what distance will it take for the car to slow down to a speed of 56 Km/h?

Answers

Answer:

[tex]1.74\times10^3 kg; 100m[/tex]

Explanation:

Step a: mass of the car. Let's grab the definition of kinetic energy: [tex]K= \frac12 mv^2[/tex]. We have K, we have v (which we should convert in meters per second, dividing by 3.6) to get:[tex]4.22\times10^5 = \frac12m(22.03)^2 \rightarrow m= 2\times4.22 / 495.22 \times 10^5 = 1.74 \times 10^3 kg[/tex]

Point a is done.

Now for the (b)reaking part. (I'm sorry, it's an horrible joke, but I couldn't resist)

In theory we have the mass, we have the force, so we could find the acceleration, find how long it takes to slow down, and then find the distance traveled. Too long. Let's do things more easily: when the car slows down to 56 km/h it will have a different kinetic energy. The difference in kinetic energy is the work done by the breaking force ofer the slowing distance.

[tex]K_f-K_i=W[/tex] A quick note on signs: if you look carefully the final kinetic energy will be less than the initial value, thus the work will be negative: it means it's correct, since the work is against the motion, slowing it down. Let's get calculating, first by converting 56 kmh in m/s (15,56 m/s), then finding the final kinetic energy:

[tex]K_f =\frac12 (1.74\times10^3) (15.56)^2 =2.11 \times 10^5 J[/tex]

The difference will be the work done by the force, or

[tex](2.11 - 4.22) \times 10^5 = \vec F\cdot \vec x=Fx[/tex] where  we are assuming that force and displacement have the same line of actions to simplify the dot product.

[tex]2.11\times 10^5 = 2100x = 1.00\times 10^2 m[/tex]

A 1300 watt hair blow dyer is designed to operate on 120 Volts. How much current does the dryer require

Answers

Answer:

10.83 Amperes

Explanation:

if   A ⇒ current

W = VA

1300 = 120 x A

1300 / 120 = A

10.83 = A

A clothes dryer in a home draws a current of 10 amps when connected on a special 220-volts household circuit.what is the resistance of the dryer?

Answers

Answer:

22Ω

Explanation:

if    V ⇒ voltage

      I ⇒ current

      R ⇒ resistance

V = IR

220 = 10 x R

220 / 10 = R

22 = R

PLEASE HELP!
A 9kg particle is initially at rest at x=0. It is subject to a single force Fx (N) which varies with x (m) as shown in the
diagram
F
2
1
0
ББ by
x
- 1
1
-2
The kinetic energy of the particle when it is at x = 3 m is:

Answers

Hi there!

With a Force/Displacement curve, we must take the integral (area underneath the curve) to calculate the work done.

We know that:

W = ΔKE

Calculate the work by finding the area underneath the force curve from

x = 0 to 3 m:

We can use a trapezoid:

A = 1/2(3 + 2)(3) = 7.5 J

This is the amount of work done, and since the object starts from rest:

7.5J = KEf - KEi (0 J)

7.5J = KEf = 7.5 J

This question has two parts. First, answer part A. Then, answer part B. Part A: Which statement best summarizes the theme of the text? O A. You do not always recognize what is most valuable. O B. Keep your friends close, but your enemies closer. W O C. Fine possessions do not make a fine person. h 0 D. The best things come in small packages. Part B: Which evidence from the text best supports your answer in part A? O A. "The other animals of the forest bowed to him, and they often spoke of his antlers with admiration." B. "The Stag was so engrossed that he did not notice that a Lion had crept up alongside him." C. ". . . but the branches of some of the trees hung low, and vines curled around them." D. "The long legs that I hated would have saved me, but the antlers that I loved have led to my destruction!"​

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Answer: for part A Its A the ANSWER for part B its D

Explanation:

Answer:

a and b

Explanation:

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