As a block of mass 42 kilograms drops from the edge of a 40-meter-high cliff it experiences a loss of energy due to air resistance of 81 J. At what speed will the rock hit the ground?

Answers

Answer 1

Answer:

The block hits the ground at 27.9 m/s

Explanation:

Gravitational Potential Energy (GPE)

It's the energy stored in an object because of its height in a gravitational field.

It can be calculated with the equation:

U=m.g.h

Where m is the mass of the object, h is the height with respect to a fixed reference, and g is the acceleration of gravity or [tex]9.8 m/s^2[/tex].

When the block is at the edge of the cliff it has potential energy that can be transformed into any other type of energy as it starts falling to the ground.

The GPE of the block of mass m=42 Kg at h=40 m is:

U = 42*9.8*40

U = 16,464 J

The block loses 81 J due to air resistance, thus the energy stored when it hits the ground is 16,464 J - 81 J = 16,383 J.

This energy is stored as kinetic energy, whose formula is:

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

Solving for v:

[tex]\displaystyle v=\sqrt{\frac{2K}{m}}[/tex]

[tex]\displaystyle v=\sqrt{\frac{2*16,383 }{42}}[/tex]

[tex]v=\sqrt{780.143}[/tex]

v = 27.9 m/s

The block hits the ground at 27.9 m/s


Related Questions

A 300 g bird flying along at 6.0 m/s sees a 10 g insect heading straight toward it with a speed of 30 m/s. the bird opens its mouth wide and enjoys a nice lunch. What is the bird's speed immediately after swallowing?

Answers

Answer:

6.77m/s

Explanation:

Using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are the velocities before collision

v is the final collision

Given

m1 = 300g  = 0.3kg

u1 = 6.0m/s

m2 = 10g = 0.01kg

u2 = 30m/s

Required

The bird's speed immediately after swallowing v

Substitute the given values into the formula

m1u1 + m2u2 = (m1+m2)v

0.3(6) + 0.01(30) = (0.3+0.01)v

1.8+0.3 = 0.31v

2.1 = 0.31v

v = 2.1/0.31

v = 6.77m/s

Hence the bird's speed immediately after swallowing is 6.77m/s

A ball of mass 4kg moving with a velocity of 20m/s collides with another ball of mass 15kg moving with a velocity of 15m/s in the same direction. Calculate the velocity of the 5kg ball if the collision is perfectly inelastic.​

Answers

Answer:

velocity = 16.05 m/s

Explanation:

inelastic collision formula:

m1u1 + m2u2 = (m1 + m2)v

m1 = 4kg

u1 = 20m/s

m2 = 15kg

u2 = 15m/s

find v ?

m1u1 + m2u2 = (m1 + m2)v

(4×20) + (15×15) = (4+15)v

80 + 225 = 19v

305 = 19v

19v = 305

v = 305/19

v = 16.05 m/s

Joe applies a force of 50 N to a box which has a mass of 15 kg. What is the acceleration of the box?
a.

Answers

Answer:

3.333 m/s^2

Explanation:

50/15 = 3.33 m/s^2

before leaving earth, the mass if an astronaut is measured to be 60kg. the astronaut lands on the moon and measures the acceleration of gravity to be 1.6 m/s^2. what is the mass of the astronaut at moon?​

Answers

Answer:

The answer is 2,475$+948= add you will get the answer rn

The weight we experience on a surface is the product of our mass and acceleration due to gravity on that surface. The mass of the astronaut in earth was 60 kg . Then his mass at moon will be 9.76 kg.

What is gravitational force ?

The gravitational force is the force by which an object attracts other objects into its center of mass. Earth attracts every objects into its center. That why we are all standing on the ground.

The weight we experience on earth is due to the gravity. That is the product of mass and acceleration due to gravity of a planet is the weight on the planet.

The weight of astronaut in earth = 60 kg

acceleration due to gravity on earth = 9.8 m/s²

mass = 60/9.8 m/s² = 6.19 kg

Acceleration due gravity on moon = 1.6 m/s²

then weight on moon = 1.6 m/s² ×6.19 kg = 9.7 kg.

Therefore, the weight of the astronaut in moon will be 9.7 kg.

Find more on gravitational force:

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a passenger of mass m on a Ferris wheel moves in a vertical circle of radius r with constant speed v assuming that the seat remains upright during the motion which is true about the force the seat exerts on the passenger at the top of the circle

the upward force is equal in magnitude to the passenger's weight
the upward force is greater in magnitude than the passenger's weight
the upward force is smaller in magnitude than the passenger's weight
the upward force is zero

Answers

Answer:

the upward force is equal to the passenger weight

The answer that is the truth about the force that the seat exerts on the passenger is the upward force is equal in magnitude to the passenger's weight.

Why the upward force is equal in magnitude to weight

The acting forces on the body has been said to be vertical. This implies that the upward force and the downward force of gravity are the same.

Using the second law of Isaac Newton, the downward direction of the forces would be ascertained.

Read more on force and magnitude here:

https://brainly.com/question/19802988

Select the correct answer.
Derick has been working as a first responder since many years. His primary responsibility at a crime scene is to question witnesses and gather
useful information from the scene. Which of these first responder career roles does Derick fit into?
OA paramedic
OB. police officer
Oc. fire truck driver
OD. firefighter

Answers

Answer:

Police officer

Explanation:

Because police officers wants to gather information on what happens and question people to know everything. That is what Derick is doing

Need help ASAP plsss

Write 5-6 sentences about
:how do parachutes work ??

Answers

A ripcord system pulls a closing pin, which releases a spring-loaded pilot chute, and opens the container; from which the parachute comes out.

If a skydiver is unable to open her/his parachute, an automatic activation device will automatically open the parachute.

A parachute works by forcing air into the front of it and creating a structured 'wing' under which the canopy pilot can fly. Parachutes are controlled by pulling down on steering lines which change the shape of the wing, cause it to turn, or to increase or decrease its rate of descent.

Use the image below to answer the question.



What does the arrow 'B' represent?
Question 7 options:

wavelength


refraction


frequency


compression

Answers

i’m pretty sure it’s c

name three characteristics of sound​

Answers

Loudness, pitch, and timbre

Suppose that the separation between two speakers A and B is 6.60 m and the speakers are vibrating in-phase. They are playing identical 126-Hz tones and the speed of sound is 343 m/s. An observer is seated at a position directly facing speaker B in such a way that his line of sight extending to B is perpendicular to the imaginary line between A and B. What is the largest possible distance between speaker B and the observer, such that he observes destructive interference

Answers

Complete question

The diagram for this question is shown on the first uploaded image

Answer:

The largest possible distance is [tex]e = 15.33 \ m[/tex]

Explanation:

From the question we are told that

   The separation between Speaker at  position  A and B  is  AB =  6.60 m

   The frequency of the tune which the speaker are playing is [tex]f = 126 \ Hz[/tex]

    The speed of sound is [tex]v = 343 \ m/s[/tex]

Generally the wavelength of the tune playing is mathematically represented as

           [tex]\lambda = \frac{v}{f}[/tex]

=>        [tex]\lambda = \frac{343}{ 126}[/tex]

=>        [tex]\lambda = 2.72 \ m[/tex]

Let the observer be at position D

Generally the distance A and  is mathematically  evaluated using  Pythagoras theorem as

       [tex]AC = \sqrt{AB ^2 + BC^2}[/tex]

Let BC = e

So  

       [tex]AC = \sqrt{6.60 ^2 + e^2}[/tex]

Generally the path difference between the first and the second speaker from the observer point of view is mathematically represented as

       [tex]P = AC - BC[/tex]

=>     [tex]P = \sqrt{6.60 ^2 + e^2} - e[/tex]

Generally the condition for destructive interference is mathematically represented as

            [tex]P = (2n - 1 )\frac{\lambda}{2}[/tex]

Here n is the order of the fringe which is  one

=>        [tex]\sqrt{6.60 ^2 + e^2} - e = (2 * 1 - 1 )\frac{2.72}{2}[/tex]

=>        [tex]\sqrt{6.60 ^2 + e^2} - e = 1.36[/tex]

=>        [tex]6.60 ^2 + e^2 =( 1.36 +e)^2[/tex]

=>        [tex]6.60 ^2 + e^2 =1.8496 + 2.72e +e^2[/tex]

=>          [tex]e = 15.33 \ m[/tex]

     

what is the difference between alcoholic and Mercury thermometer based on their function? ​

Answers

Alcohol filled thermometer is used for low temperature applications. (Weather) It’s freezing point is -70 degC
While mercury freezes at -38 deg C

Mercury is/was better for human and other animal temps. High thermal coefficient of expansion mercury vs. alcohol = better resolution for small temperature changes in a medical application.

For higher temperatures alcohol will boil before mercury will.



identical spheres are dropped from a height of 100 m above the surfaces of Planet X and Planet Y. The speed of the spheres as a function of time is recorded for each planet in the graph
above. Which planet exerts the greater force of gravity on the sphere, and what evidence supports this conclusion?
A Planet X because its line has the greater area under it.
Planet X, because its line has the greater slope
Planet Y. because it falls for the smaller amount of time
Planet Y because the object's final speed is greater

Answers

Answer:

B. Planet X, because its line has the greater slope.

Explanation:

In a speed graph, acceleration is slope. A greater slope means a greater acceleration. According to Newton's 2nd law (F=mg), a greater acceleration means a greater force.

Planet X exerts the greater force of gravity on the sphere, because its line has the greater slope. Hence option B is correct.

What is Gravitational Force ?

Gravitational force is force of attraction between two masses. Gravitational force(F) between two bodies is directly proportion to the product of masses(m₁,m₂) of two bodies and inversely proportional to square of distance(r) between them. mathematically it is written as,

F ∝ m₁.m₂

F ∝ 1/r²

F = G m₁,m₂÷r²

where G is gravitational constant, whose value is 6.6743 × 10⁻¹¹ m³ kg-1s⁻².

Force is expressed in Newton N in SI unit. its dimensions are [M¹L¹T⁻²].

This is analogous with coulomb's law which gives force between two charges.

if a planet has greater gravitational force(force of gravity), then body falls with greater speed as compare to other planet which is having less force of gravity. we can see in case of planet X there is greater speed as compare to plane Y in short time. Hence option B is correct.

To know more about Gravity :

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What is the force (in Newtons, 1 Newton = 1Kgm/s2) required to accelerate a 1500 Kg car to 3 m/s2?

Answers

Answer:

F=4500N

Explanation:

F=m×g

F=1500kg×3m/s²

F=4500N

Answer:

F=4500N

Explanation:

F=m×g

F=1500kg×3m/s²

F=4500N

A Ferris wheel with 60 spokes has a diameter of 100 m. It makes one rotation every 60 seconds. Find the speed of the passengers when the Ferris wheel is rotating at this rate.

Answers

Answer:

The speed of the passengers is 5.24 m/s

Explanation:

Uniform Circular Motion

It occurs when an object in a circular path travels equal angles in equal times.

The angular speed can be calculated in two different ways:

[tex]\displaystyle \omega=\frac{v}{r}[/tex]

Where:

v = tangential speed

r = radius of the circle described by the rotating object

Also:

[tex]\omega=2\pi f[/tex]

Where:

f = frequency

Since the frequency is calculated when the number of revolutions n and the time t are known:

[tex]\displaystyle f=\frac{n}{t}[/tex]

The Ferris wheel has a diameter of 100 m and makes n=1 rotation in t=60 seconds, thus the frequency is:

[tex]\displaystyle f=\frac{1}{60}\ Hz[/tex]

The angular speed is:

[tex]\displaystyle \omega=2\pi \frac{1}{60} =\frac{\pi}{30} \ rad/s[/tex]

Now we calculate the tangential speed, solving this formula for v:

[tex]\displaystyle \omega=\frac{v}{r}[/tex]

[tex]v=\omega . r[/tex]

The radius is half the diameter, r=100/2=50 m:

[tex]\displaystyle v=\frac{\pi}{30} . 50[/tex]

Calculating:

v = 5.24 m/s

The speed of the passengers is 5.24 m/s

Pelican hunts fish in the water as th pelican the waters surface why must it aim for the fish in a slightly different place than where the fish appears to be located​

Answers

The Pelican  must aim differently than where the fish appears to be because light is refracted from air to water.

Refraction is the change in the direction of a wave at the interface between two media. The effects of refraction are easily seen when light is travelling from air to water hence objects are not really where they appear to be when viewed above the water surface.

Hence, the Pelican  must aim differently than where the fish appears to be because light is refracted from air to water.

Learn more about refraction: https://brainly.com/question/11155928

a machine
of efficiency of 70% is used to raise
a body of
mass 80 kg through
a vertical distance of 3m in
40 seconds. Calculate the power input. (Take g = 10 m/s²)​

Answers

Answer:

Power_input = 85.71 [W]

Explanation:

To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.

[tex]W = F*d[/tex]

where:

W = work [J] (units of Joules)

F = force [N] (units of Newton)

d = distance [m]

We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.

Now replacing:

[tex]W = (80*10)*3\\W = 2400 [J][/tex]

Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.

[tex]P=\frac{W}{t}[/tex]

where:

P = power [W] (units of watts)

W = work [J]

t = time = 40 [s]

[tex]P = 2400/40\\P = 60 [W][/tex]

The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.

[tex]Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}=60/0.7\\P_{introduced}=85.71[W][/tex]

If forces acting on an object are unbalanced, the object could experience a change in ________.

mass, speed, or direction
negative acceleration or mass
direction, mass, or both
speed, direction, or both

Answers

Speed is the answer

D) Speed, direction, or both

Mass doesn’t just CHANGE like that.

Define specific vision??​

Answers

Answer:an inspirational statement of an idealistic emotional future

Explanation:

I don't know if it's right tho

Answer:

The document that state tge currentand future objectives of an organization.

What are some ways that the Greeks demonstrated their passion for public life?

Answers

Art Showed their love and loyalty.

Answer:

The Greeks had drama and arts competitions that were considered very popular, and important in society.

Explanation:

hope it helps!

What is unique regarding the abdominal muscle when is compared to other muscle in the body?

(A) it is a very large muscle
(B) it does not develop easily
(C) it can move the body either from the ribcage or the pelvis.
(D) it can get injured easily if you perform a lot os repetitions.
(E) none of the above

Answers

Answer:a is the answer

A herdsman yelling out to a fellow herdsman heard his voice reflected by a cliff 4s later.What is
the velocity of sound in air if the cliff is 680m away​

Answers

Answer:

v = 340 m/s

Explanation:

Given that,

A herdsman yelling out to a fellow herdsman heard his voice reflected by a cliff 4s later.

The cliff is 680 m away

We need to find the velocity of sound in air.

Velocity = distance/time

Distance = 2 × 680 = 1360 m

[tex]v=\dfrac{1360\ m}{4\ s}\\\\=340\ m/s[/tex]

So, the velocity of sound in air is 340 m/s.

A phosphodiester bond is used to:

A. Join glycerol to fatty acids
B. Join two nucleotides into a polynucleotide
C. Join two glucose molecules
D. Join two amino acids into a polypeptide

Answers

Answer:

A. Join glycerol to fatty acids

Explanation:

I majored in Physics.

I think it’s A I believe sorry if I get it wrong

Do YOU think aliens are real? HELP PLS
Which answer best displays Adam's use of the civic virtue "diversity"?

Diversity means something is benifical to an entire group.

Diversity means fair treatment of all people the

Answers

Answer:Yes

Explanation:yeah i think it could be possible because the universe is so far and wide its probably infinite and if we did i personally believe that we would be absolutely be annihilated by them because we would be so far behind technology wise we would have no use for the\

YOU FELL FOR IT FOOL THUNDER CROSS SPLIT ATTACK

Which of the following is an opinion about friction?
It always acts in the opposite direction as the motion of the object.
It stops objects on Earth from staying in motion forever.
It slows objects down too much.
It happens any time two objects are in contact.

Help me out please-
You'll get 40 points

Answers

My opinion about friction is that It always acts in the opposite direction as the motion of the object.

What is friction?

Friction refers to the resistance of motion of one object that is moving relative to another object. Fricton has many application but it has also many disadvantages.

So we can conclude that friction is always acts in the opposite direction as the motion of the object.

Learn more about friction here: https://brainly.com/question/24338873


The rate of change of velocity or speed is known as acceleration. If a car increases it speed form 10 to 20m/s in 2 seconds, then what is its rate of change in velocity?
A) 5 m/s/s
B) 10 m/s/s
C) 20 m/s/s
D) 40 m/s/s

Answers

Answer:

A) 5 m/s/s

Explanation:

Given the following data;

Initial velocity = 10m/s²

Final velocity = 20m/s²

Time, t = 2 seconds.

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.

Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.

Mathematically, acceleration is given by the equation;

[tex]Acceleration, a = \frac{final \; velocity - initial \; velocity}{time}[/tex]

Substituting into the equation, we have;

[tex]Acceleration, a = \frac{20 - 10}{2}[/tex]

[tex]Acceleration, a = \frac{10}{2}[/tex]

Acceleration, a = 5m/s²

True/False: The Earth's core is completely solid, and the only liquid portion of the Earth's layers is the crust.

Answers

Answer:

true i believe

Explanation:

Answer:

true

Explanation:

true because other guy said it lol

According to The Flash, The heroes top speed is Mach 3.3, or 2,500 miles per hour. How
long would it take for him to run around the planet? (circumference of the earth is
roughly 25,000 miles) *

Answers

Answer:

nearly 2 days or less hes fast but not that fast

Explanation:

but maybe he can run it in five minutes

You have to move your 100 N couch before a delivery company drops off your new one. Unfortunately your roommate is passed out on it. The coefficient of friction between the couch and floor is .43. It takes 250 N of force to get the couch moving. a) How much does your roommate weigh in Newton’s? b) After you get the couch moving it only takes 200 N to keep it moving at a constant speed, what is the coefficient of kinetic friction?

Answers

Answer:

a) Weight of Roommate = 481.4 N

b) μk = 0.34

Explanation:

a)

The force required to move the couch must be equal to the force of friction:

F = frictional force

F = μW

W = F/μ

where,

W = Total Weight of Couch and Roommate

F = Force Required start to move couch = 250 N

μ = coefficient of static friction between couch and floor = 0.43

Therefore,

[tex]W = \frac{250 N}{0.43}\\\\W = 581.4 N[/tex]

So, the total weight is given as:

W = Weight of Couch + Weight of Roommate

Weight of Roommate = W - Weight of Couch

Weight of Roommate = 581.4 N - 100 N

Weight of Roommate = 481.4 N

b)

Now, the force required to keep the couch moving can be given as equal to the kinetic friction force:

F = kinetic friction

F = μk*W

μk = F/W

where,

μk = coefficient of kinetic friction = ?

F = Force required to keep the couch moving = 200 N

Therefore,

μk = 200 N/581.4 N

μk = 0.34

how is red shift evidence of the big bang
it implies our universe is expanding
it implies our universe is collapsing
it implies our universe is standing still

Answers

Answer:

it implies our universe is expanding

An astronaut floating at rest in space throws a wrench in one direction and subsequently recoils back with a velocity in the opposite direction. Which of the following statements is/are true?
I. The velocity of the wrench is equal and opposite to the velocity of the astronaut.
Il. The momentum of the wrench is equal and opposite to the momentum of the astronaut.
III. The impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut
a) ll and ill only
b) I only II only
c) I, II, and III
d) I and Il only

Answers

Answer:

a) ll and Ill only

Explanation:

Let the mass of the wrench = m

and the mass of the astronaut = M

Initially, the velocity of the astronaut and wrench are zero.

The astronaut throws the wrench in one direction and subsequently recoils back with a velocity in the opposite direction.

Let v and V be the velocity of the wrench and the velocity of the astronaut respectively.

In space, there is no external force acting, the momentum must be conserved.

So, m(0)+M(0)=m(v)+M(V)

So, 0=mv+MV

[tex]\Rightarrow mv=-MV[/tex] ...(i)

Here, the momentum of the wrench = mv, and the momentum of the astronaut= MV. The negative sign showing that both the momentum are in opposite direction.

Therefore, the momentum of the wrench is equal and opposite to the momentum of the astronaut.

According to Newton's second law, the rate of change of momentum = applied force.

Let it take [tex]\Delta t[/tex] seconds to change the momentum.

So, for the wrench

[tex]m(v-0)/\Delta t= F_w \\\\\Rightarrow m(v-0)=F_w\Delta t \\\\\Rightarrow mv=F_w\Delta t \cdots(ii)[/tex]

Here, [tex]F_w\Delta t[/tex] is the impulse applied to the wrench.

Similarly, for the astronaut

[tex]M(-V-0)/\Delta t= F_a[/tex] [negative sign (-V) for opposite direction]

[tex]\Rightarrow M(-V-0)=F_a\Delta t \\\\\Rightarrow -MV=F_a\Delta t[/tex]

Here, [tex]F_a\Delta t[/tex] is the impulse applied to the astronaut.

So, the impulse on the astronaut.

By using equations (i) and (ii)

[tex]F_a\Delta t=F_w\Delta t[/tex]

Therefore, the impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut.

Hence, option (a) is correct.

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A scale measures weight to the nearest 0.5 pound. Which measurementshows an appropriate level of precision for the scale?A. 140 poundsB. 140.5 poundsC. 140.75 poundsO D. 141 pounds which of the following statements is FALSE? a. alleles are made when one original DNA strand experiences mutations that result in phenotypes that offer advantages b. the DNA of two alleles must be almost identical. since the trait is the same. But the effect of the allele may be very different! c. in humans, for every trait we can only have two alleles. but that trait can be controlled by many alleles. there are no limits on how many alleles can control a trait. d. being diploid means that humans cannot mask the effects of recessive alleles. humans always show both alleles in their phenotypes and genotypes e. if humans were diploid we would only have one allele per traitHelpppp pleaseee The equation y = 3x + 7 is written in slope-intercept form.O TrueFalse Can somebody plz answer these questions correctly thanks!!WILLL MARK BRAINLIEST WHOEVER ANSWERS FIRST! :DDD NEED HELP ASAP PLEASE! Riverrun Co. provides medical care and insurance benefits to its retirees. In the current year, Riverrun agrees to pay $31,500 for medical insurance and contribute an additional $9,650 to a retirement program. Record the entry for these accrued (but unpaid) benefits on December 31. USA test prep please help you have a friend who is using a recipe for flat from american cookbook you notice that he set your over temperature at 175F what you advise him to do? When members of a community work to preserve their unique cultural traits, they are trying to protect their __________. A. universal culture B. cultural region C. popular culture D. local culture Please select the best answer from the choices provided A B C D Mark this and return will give brainliest :) Why is a president also known as the commander-in-chief Explain applicationsMRIX-rayUltrasoundInfrared Radiation PLZ HELP The function shown models the total number of insects in a colony x months after a small number of the insects are brought into a region. What was the total number of insects in the colony when they were first brought into the region ? Enter your answer in the box 2. Media sharing websites let you post photos and videos to share with other people. What are the benefits and drawbacks of using these websites? Calculate the percentage composition of a hypothetical compound, X2Y3. The molar mass of X is 4.53 g/mol and the molar mass of Y is 8.71 g/mol. Round both answers to whole numbers. What is the answer for my khan academy homework Jonas exclaims that The Giver has so much "power." The Giver then corrects Jonas by using the word "honor" instead. Which answer best explains why the author includes this in chapter 11? A.Jonas is going to find that honor is not the same as power in the upcoming chapters.B. The author wanted to compare & contrast the two words.C.Power only means strength, so the author wanted to show that Jonas lacks that.D.The author wanted to show that The Giver is harsh on Jonas. Which of the following best describes an ecosystem in a neighborhood garden? The cost of 5 scarves is $31.25. What is the unit price? 11 is what percent of 300?