You testify as an expert witness in a case involving an accident in which car A slid into the rear of car B, which was stopped at a red light along a road headed down a hill (Fig. 6-25). You find that the slope of the hill is u " 12.03, that the cars were separated by distance d " 24.0 m when the driver of car A put the car into a slide (it lacked any automatic anti-brake-lock system), and that the speed of car A at the onset of braking was v0 " 18.0 m/s.With what speed did car A hit car B if the coefficient of kinetic friction was (a) 0.60 (dry road surface) and (b) 0.10 (road surface covered with wet leaves)

Answers

Answer 1

Answer:

A) 12.08 m/s

B) 19.39 m/s

Explanation:

A) Down the hill, we will apply Newton’s second law of motion in the downward direction to get:

mg(sinθ) – F_k = ma

Where; F_k is frictional force due to kinetic friction given by the formula;

F_k = (μ_k) × F_n

F_n is normal force given by mgcosθ

Thus;

F_k = μ_k(mg cosθ)

We now have;

mg(sinθ) – μ_k(mg cosθ) = ma

Dividing through by m to get;

g(sinθ) – μ_k(g cosθ) = a

a = 9.8(sin 12.03) - 0.6(9.8 × cos 12.03)

a = -3.71 m/s²

We are told that distance d = 24.0 m and v_o = 18 m/s

Using newton's 3rd equation of motion, we have;

v = √(v_o² + 2ad)

v = √(18² + (2 × -3.71 × 24))

v = 12.08 m/s

B) Now, μ_k = 0.10

Thus;

a = 9.8(sin 12.03) - 0.1(9.8 × cos 12.03)

a = 1.08 m/s²

Using newton's 3rd equation of motion, we have;

v = √(v_o + 2ad)

v = √(18² + (2 × 1.08 × 24))

v = 19.39 m/s


Related Questions

A car has a velocity of 10m/s.it now accelerates for 1m/s for 1/4 minutes. Find the distance travelled in this time and final speed of the car​

Answers

¡Hellow!

For this problem, lets recabe information:

v (Velocity) = 10 m/s

a (Aceleration) = 1 m/s²

t (Time) = 1/4 min = 25 s

d (Distance) = ?

v' (Final velocity) = ?

First, for calculate distance, lets applicate formula:

                                        [tex]\boxed{\boxed{\text{d = Vo * t + (a * t}^{2})\text{ * 0,5} } }[/tex]

Lets replace according we information and let's resolve it:

d = 10 m/s * 25 s + (1 m/s² * (25 s)²) * 0,5

d = 250 m + (625 m) * 0,5

d = 2,5 m + 312,5 m

d = 314 meters.

Now, for calculate final speed, lets applicate formula:

                                                 [tex]\boxed{\boxed{\text{v' = v + a * t} } }[/tex]

Lets replace according we information and let's resolve it:

v' = 10 m/s + 1 m/s² * 25 s

v' = 10 m/s + 25 m/s

v' = 35 m/s

¿Good Luck?

Att: That guy who use the "ñ".

Which of these warnings refers to a chemical property of the material?

Answers

Answer:

Please show the warning's

Explanation:

The warning refers to the chemical property of the material or object that is flammable.

What is Chemical Property?

A chemical property is a feature that pertains to how a component, such as an ingredient or a compound, can alter as a result of a reaction. Due to bonding and other atomic structural characteristics, a substance develops these qualities as a result of its chemical identity.

Tactile or visual changes may occur in conjunction with chemical qualities. Chemical reactions commonly involve popping, fizzing, or the release of brilliant light. The emission of heat may also be a sign of a chemical reaction or chemical conversion that is taking place. Because the connections in the atomic structure are changing or breaking, these sensory clues appear.

Therefore, the warning refers to a chemical property of the material is flammable or combustible.

To know more about chemical property:

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it takes 275n to set a stationary 77.3 crate in motion. what is the coefficient of static friction?

Answers

Note: I'm assuming the data 77.3 is the mass of the crate.

Answer:

[tex]\mu_s =0.36[/tex]

Explanation:

The coefficient of static friction, called \mu_s is the ratio between the force needed to start moving an object above a rough surface (Fr), and the normal force the surface exerts on the object (N).

[tex]\displaystyle \mu_s =\frac{Fr}{N}[/tex]

The normal force is numerical equivalent to the weight of the body if no other external forces are acting.

[tex]N=m\cdot g[/tex]

The mass of the crate is m=77.3 Kg, thus its weight and normal force is:

[tex]N=77.3\ kg\cdot 9.8\ m/s^2[/tex]

[tex]N= 757.54\ Nw[/tex]

Now we calculate the coefficient:

[tex]\displaystyle \mu_s =\frac{275\cancel{N}}{757.54\cancel{N}}[/tex]

[tex]\boxed{\mu_s =0.36}[/tex]

Answer:

0.36

Explanation:

A tennis ball, 0.384 kg, is accelerated at a rate of 187 m/s2 when hit by a professional tennis player. What force does the player's tennis racket exert on the ball?

Answers

Answer:

The answer is 71.81 N

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 0.384 × 187 = 71.808

We have the final answer as

71.81 N

Hope this helps you

what is an ammeter used for ?How can it be connected to make a measurement for a circuit component​

Answers

Answer:

See the explanation below.

Explanation:

An ammeter is an instrument for measuring electrical currents in a circuit. To measure the current the ammeter must be connected in series with the circuit so that the current flows through it. At present time there are modern instruments such as the amperimetric clamp, which also serves to measure currents in a more easy way

if an object measures to be 80 centimeters in length, then it is equivalent to ____​

Answers

Answer:

31.496 inches

Explanation:

How does increasing frequency affect the crests of a wave?

Answers

Answer:

your getting in the water causes it to make a giant wave

Explanation:

How long will it take a person walking at 2.1 m/s to travel 13 m?

Answers

Answer:

I gonna give you the number so but you need to round 6.19047619048

Explanation:

This is a speed formula so you would use the formula speed=distance/timeYou need to rearrange it to time=distance/speedSo you need to divide 13m by 2.1 m/s

The speed of an object undergoing constant acceleration increases from 8.0 m/s to 12.0 m/s in 10.0 seconds. How far does the object travel during the
10.0 seconds?
4 m
100 m
800 m
10 m

Answers

Answer:

is the question finnished

Explanation:

Rock X is released from rest at the top of a cliff is on earth. A short time later, Rock y is released from rest from the same point as rock X. Both rocks fall for several seconds before landing on the ground directly below the cliff. Frictional forces are considered to be negligible. Which of the following graph correctly shows the vertical velocity of rock X as a function of time? Take the positive direction to the upward.​

Answers

Answer:

The graph that correctly shows the vertical velocity is B. since the velocity is negative and increases linearly over time

Explanation:

When an object is dropped from rest its movement is ruled only by the effect of gravity.

The acceleration of gravity [tex]g=9.8\ m/s^2[/tex] makes the object gain speed with a linear relation as shown:

vf = g.t

If we take the positive direction to be upward, then the speed will always be negative since the object will go against the positive direction.

Thus, the graph that correctly shows the vertical velocity is B. since the velocity is negative and increases linearly over time

From the given graphs, only the second graph (option B) started from rest (0) and later increased with time.

The given parameters;

Rock XRock yinitial velocity of Rock X = 0

The final vertical velocity of the rock X after a short time "t" is calculated as follows;

[tex]v_y_f = v_y_i + gt\\\\v_y_f = 0 + 9.8t[/tex]

The vertical velocity of the rock x will increase with time as it moves downwards.

Therefore, we can conclude that, from the given graphs, only the second graph (option B) started from rest (0) and later increased with time.

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Select the correct answer.
Which statement is true?
Ο Α. .
The speed of sound in air is inversely proportional to the temperature of the air.
OB.
The speed of sound in air is directly proportional to the temperature of the air.
The speed of sound in air is twice the temperature of the air.
OD
The speed of sound in air is not affected by the temperature of the air.

Answers

Let me think I think it’s B
I'm sure the correct answer is B.

What is the resultant of 5N force pointing north and 7N force pointing south? Do not forget to include the direction.

Answers

Answer:

It would be 2N pointing South.

Explanation:

Since the forces are going in opposite directions, you can subtract them. Which makes it 7N south minus 5N North. That is 2N pointing South. Because the force going south is greater, it is the direction the force will be going.

Which of the following might be the material list for an experiment?
A data tables and graphs
B.meters, liters, and kilograms
C plastic containers, soil, water, thermometers, and plants
D temperature, light, and time​

Answers

Answer:

C

Explanation:

The two factors that determine velocity are....
A: speed and direction
B: direction and distance
C: position and rate
D: distance and mass


please help which one are these . for science class

Answers

Answer:

Explanation:

D Distance and Mass

We act out our forbidden fantasies in our dreams.
a. True
b. False

Answers

Yes that’s true we do act out our forbidden fantasies in our dreams.

In a powder-flavored drink solution, which substance is the solvent?
a. glass
b. flavored powder
c. water
d. sugar

Answers

Answer:

c. Water

Explanation:

The solvent is the substance in which a solute is dissolved to make the solution.

In this case, the water is the solvent, the flavored powder is the solute, and the solution is the final drink.

when a light bulb is turned on electrical energy is transformed into two other types of energy. What are they and support your answer

Answers

Answer:

In the case of an electric bulb, the electrical energy is converted to light and heat. The amount of electrical energy put into a bulb = the amount of light energy (desirable form) plus the heat energy that comes out of the bulb (undesirable form).

Explanation:

sana nakatulong)):

x = yz
How do you solve for z?

Answers

Answer. z=x/y. Isolate “z” by dividing “y” from both sides.
Explanation. Treat the variables like any other number(s). We can plug in numbers but you don’t have to. We must isolate z to get the answer. To do this, divide both sides by y and you get your answer of z=x/y. Hope this helps, let me know if it’s correct so others can use it :)
Good luck.

1 pts
How can two different nonmetals form a compound?

Answers

Explanation:

Covalent or molecular compounds form when elements share electrons in a covalent bond to form molecules. Molecular compounds are electrically neutral. Ionic compounds are (usually) formed when a metal reacts with a nonmetal (or a polyatomic ion). Covalent compounds are formed when two nonmetals react with each other.

Nonmetals can form compounds through a process called covalent bonding.

Covalent bonding occurs when two nonmetal atoms share electrons to achieve a stable electron configuration. This sharing of electrons allows both atoms to fill their outermost energy levels or achieve a noble gas electron configuration.

When two nonmetal atoms come together to form a compound, their electronegativities play a crucial role. Electronegativity is the ability of an atom to attract electrons toward itself in a chemical bond. If the electronegativities of the two nonmetals are similar, they will have a similar tendency to attract electrons, resulting in a more equal sharing of electrons.

So, nonmetals can form compounds through covalent bonding by sharing electrons. The extent of electron sharing depends on the electronegativity difference between the nonmetals involved, leading to either polar covalent or ionic bonding.

Therefore, nonmetals can form compounds through a process called covalent bonding.

To know more about covalent bonding, click here:

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Light and sound waves both share what characteristic?
A: they both exhibit the doppler effect
B: light and sound are both transverse waves
C: they both move fastest in water
D: light and sound both require medium in which to travel

Answers

Answer i know they both exhibit the doppler effect, so i believe it is this one.

Explanation:

Ancient gold coins have been found in Greece and Italy. What property allows for gold to be stamped into coins?

Answers

Answer: malleability

Explanation:

Help, please
and explain

Answers

We could tell a force is acting on an object if the object is being pushed, pulled, or moved in any way

Which of these objects are malleable? Check all that apply.

- tin fork and knife from camping set
- antique ceramic vase
- steel poke fence post
- marble sculpture
- glass tabletop
- copper coin

Answers

Answer:

Tin fork and knife.....Copper coin...steel pole

Explanation:

Malleable objects are those which could be shaped with out breaking or could be turned into wires. Tin fork and knife could be bent so it is malleable, copper could be turned into wires so it is also malleable. Most of the metals are malleable. Mild Steel is used in making poles and pipes which is malleable

Answer:

A C F or tin fork and knife from camping set

steel pole fence post

copper coin

Explanation:

I got it right on edg

                                                    hope it helps :)

Which statements describe vectors? Check all that apply.

Vectors have magnitude only.
Vectors have direction only.
Vectors have both magnitude and direction.
Vectors are drawn using a curved line.
Vectors are drawn using an arrow.

Answers

Answer: #3 and #5

Explanation:

A volleyball dug out by the opponent popped straight up into the air. It takes 2.05 seconds for the ball to reach its peak. Determine the height to which the ball flies. So far, I got the givens of t=2.05 seconds x=? a=9.8 meter per seconds squared final velocity=0 m/s they might be wrong though so help please!!!!

Answers

Answer:

The height to which the ball flies is 86.6 m.

Explanation:

Given that,

Time = 2.05 sec

Acceleration = 9.8 m/s²

We need to calculate the initial velocity of volleyball

Using equation of motion

[tex]v=u-at[/tex]

Where, u = initial velocity

a = acceleration

t = time

Put the value into the formula

[tex]0=u-9.8\times(2.05)^2[/tex]

[tex]u=41.2\ m/s[/tex]

We need to calculate the height of the the ball

Using equation of motion

[tex]v^2=u^2-2ah[/tex]

Put the value into the formula

[tex]0=(41.2)^2-2\times9.8\times h[/tex]

[tex]h=\dfrac{(41.2)^2}{2\times9.8}[/tex]

[tex]h=86.6\ m[/tex]

Hence, The height to which the ball flies is 86.6 m.

Elements in the same______
are more chemically similar.
THIS IS URGENT!!!!

Answers

Answer:

group

Explanation:

And vote me brainliest

They are in the same group

THIS ONE IS URGENT!!!

Examine the drawing of a molecule. Each ring represents an atom of nitrogen (N). What's the chemical formula of this
substance?

Answers

Hi :)

The chemical formula for nitrogen gas is N2.

Nitrogen gas is one of the diatomic elements, in which one molecule consists of two atoms of the same element bonded by one or more covalent bonds.

Answer:

The chemical formula for nitrogen gas is N2.

Explanation:

I just did this question and this was the correct answer!

What is the mass of a 7 kg bowling ball on the moon?

Answers

Answer:

7 kg

Explanation:

Mass remains the same, regardless of gravity. If the mass of the bowling ball is 7kg on Earth, the mass on the moon will be 7kg as well.

Speed can be represented by many different ____________________ of distance and time.

Answers

Units is the correct answer

Speed can be represented by many different units of distance and time.

What is speed?

The speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity.

Speed is defined as distance per unit time so it's unit are meter per sec, kilo-meter per hour, that is different unit of distance and time.

Speed can be represented by many different units of distance and time.

To learn more about speed refer to the link:

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What unit is force always in?
Pounds
Kilograms
Meters
Newtons

Answers

The answer would be newtons.

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