Answer:
c. Cos θ = [tex]A_{x}[/tex] / [tex]\sqrt{(A_{x} ^{2} + A_{y} ^{2}) }[/tex]
Explanation:
A vector is any quantity that has both magnitude and direction. The given vector A has components [tex]A_{x}[/tex] and [tex]A_{y}[/tex], and makes angle θ with +x axis.
Thus;
Resultant of the vector, A = [tex]\sqrt{(A_{x} ^{2} + A_{y} ^{2}) }[/tex]
Therefore, the components, angle and resultant of vector A can be represented in magnitude and direction by the three sides of a right angled triangle.
Applying the appropriate trigonometric function to the triangle for vector A, we have;
Cos θ = [tex]A_{x}[/tex] ÷ [tex]\sqrt{(A_{x} ^{2} + A_{y} ^{2}) }[/tex]
⇒ Cos θ = [tex]A_{x}[/tex] / [tex]\sqrt{(A_{x} ^{2} + A_{y} ^{2}) }[/tex]
The correct option is C.
By what factor is the heat flow increased if a window 0.550 mm on a side is inserted in the door? The glass is 0.450 cmcm, and the glass has a thermal conductivity of 0.80 W/(m⋅K)W/(m⋅K). The air films on the two sides of the glass have a total thermal resistance that is the same as an additional 12.0 cmcm of glass.
This question is incomplete, the complete question is;
A carpenter builds a solid wood door with dimensions 1.95 m × 0.99 m × 4.5 cm . Its thermal conductivity is k=0.120W/(m.K). The air films on the inner and outer surfaces of the door have the same combined thermal resistance as an additional 1.6 cm thickness of solid wood. The inside air temperature is 19.0°C , and the outside air temperature is -6.50°C .
a) What is the rate of heat flow through the door?
b) By what factor is the heat flow increased if a window 0.550 m on a side is inserted in the door? The glass is 0.450 cm , and the glass has a thermal conductivity of 0.80 W/(m.K). The air films on the two sides of the glass have a total thermal resistance that is the same as an additional 12.0 cm of glass.
Answer:
a) the rate of heat flow through the door is 97 watts
b) The factor of increased heat flow is 1.353
Explanation:
Given that;
room dimension = 1.95m × 0.99m × 4.5cm,
thermal conductivity = 0.120 w/m.k
additional thickness of solid wood Δt = 1.6 cm
a)
first we determine the effective thickness of the door;
t = 4.5cm + 1.6 cm = 61 cm ≈ 0.061 m
Now rate of heat flow is given by the relation
Q = KA( (TH -TC)/L)
= 0.12 × (1.95 m × 0.99 m) × ( (19°C - (-6.50°C)) / 0.061m)
= 0.23166 × 418.0327
= 96.8414 watts
Q = 97 watts
therefore the rate of heat flow through the door is 97 watts
b)
by intensity the glass of thickness 0.450 cm
the effective thickness is
L = 0.45cm + 12 cm = 12.45 cm = 0.1245 m
additionally area of glass A = (0.550 m)²
A = 0.3025 m²
Now
Qglass = KA ((TH-TC)/L)
= 0.80 w/m.k × 0.3025 m² × (19°C - (-6.50°C)) / 0.1245m)
= 0.242 × 204.819
Qglass = 49.57 watt
Qwood = KA ((TH-TC)/L)
area of wooden door = (1.95×0.99) - 0.3025 m² = 1.628m²
so Qwood = 0.12 × 1.628 × (19°C - (-6.50°C)) / 0.061m)
= 0.19536 × 418.0327
Qwood = 81.67 watt
Q = Qglass + Qwood
Q = 49.57 watt + 81.67 watt
Q = 131.24 watt
The factor of increased heat flow is;
f = 131.24 watt / 97 watts
f = 1.353
Is rock a substance or homogeneous or heterogeneous
Answer:
substances is ur answer dear mate
comment in the comment section
Answer: A rock is a substance.
Explanation: Rock is a substance because a rock does no have genes like you and I. And most rocks are made of sediment. That have been compressed together overtime.
How is it possible charge electrical devices when the power is out?
Answer:
generator
Explanation:
it can run an electric current to an outlet and let it charge
It was once recorded that a Jaguar
left skid marks that were 290 min
length. Assuming that the Jaguar
skidded to a stop with a constant
acceleration of -8.90 m/s2,
determine the speed of the Jaguar
before it began to skid.
Answer:
71.85 m/s
Explanation:
Given the following :
Length of skid marks left by jaguar (s) = 290 m
Skidding Acceleration (a) = - 8.90m/s²
Final velocity of jaguar (v) = 0
Speed of Jaguar before it Began to skid =?
Hence, initial speed of jaguar could be obtained using the formula :
v² = u² + 2as
Where
v = final speed of jaguar ; u = initial speed of jaguar(before it Began to skid) ; a = acceleration of jaguar ; s = distance /length of skid marks left by jaguar
0² = u² + (2 × (-8.90) × 290)
0 = u² + (-5,162)
u² = 5162
Take the square root of both sides
u = √5162
u = 71.847 m/s
u = 71.85m/s
An electric field is applied to a solution containing bromide ions. As a result, the ions move through the solution with an average drift speed of 3.0 × 10−7 m/s. The mobility of bromide ions in solution is 8.1 × 10−8 (m/s)/(N/C). What is the magnitude of the net electric field inside the solution?
Answer:
The magnitude of the net electric field inside the solution is 3.704 N/C
Explanation:
Given;
average drift speed, v = 3 x 10⁻⁷ m/s
mobility of the bromide ions, μ = 8.1 x 10⁻⁸ (m/s)(N/C)
The magnitude of the net electric field inside the solution is given by the equation below;
[tex]E = \frac{v}{\mu}[/tex]
where;
E is the magnitude of the net electric field inside the solution
Substitute the given values and solve for E
[tex]E = \frac{v}{\mu}\\\\E = \frac{3*10^{-7}}{8.1*10^{-8}}\\\\ E = 3.704 \ N/C[/tex]
Therefore, the magnitude of the net electric field inside the solution is 3.704 N/C
Car B is following car A as they are moving along a straight path with vA=40 mph and vB=45 mph. At the moment when the distance between the cars is 45 ft brakes are applied simultaneously in both cars. Car A decelerates with aA=−22 ft/s2 and car B with aB=−20 ft/s2. What is the distance between the cars when they are both stopped?
Answer:
s = 14.3 ft
Explanation:
First we need to calculate the distances traveled by both the cars. We use third equation of motion for that:
2as = Vf² - Vi²
where,
a = acceleration
s = distance
Vf = Final Velocity
Vi = Initial velocity
FOR CAR A:
Vi = Va = (40 mph)(5280 ft/1 mile)(1 h/3600 s) = 58.66 ft/s
Vf = 0 ft/s
a = aA = - 22 ft/s²
s = sa = ?
Therefore,
2(- 22 ft/s²)(sa) = (58.66 ft/s)² - (0 ft/s)²
sa = 78.2 ft
FOR CAR B:
Vi = Vb = (45 mph)(5280 ft/1 mile)(1 h/3600 s) = 66 ft/s
Vf = 0 ft/s
a = aB = - 20 ft/s²
s = sb = ?
Therefore,
2(- 20 ft/s²)(sb) = (66 ft/s)² - (0 ft/s)²
sb = 108.9 ft
Since, the car A was initially 45 ft ahead of car B. Therefore,
sa = 45 ft + 78.2 ft = 123.2 ft
Now, the distance between the cars will be:
s = sa - sb
s = 123.2 ft - 108.9 ft
s = 14.3 ft
A displacement vector points in a direction of θ = 23° left of the positive y-axis. The magnitude of this vector is D = 155 m. Refer to the figure. Enter an expression for the x-component vector, Dx, in terms of D, θ, and the unit vectors i and j.
Answer:
Dₓ = -155 sin 23° i + 0 j
Explanation:
The diagram showing the vector has been attached to this response.
As shown in the diagram,
The vector D has an x-component (also called horizontal component) of -D sinθ i. i.e
Dₓ = -D sin θ i [The negative sign shows that D lies in the negative x direction]
Where;
D = magnitude of D = 155m
θ = direction of D = 23°
Therefore;
Dₓ = -155 sin 23° i
Since Dₓ represents the x component, its unit vector, j component has a value of 0.
Therefore, Dₓ can be written in terms of D, θ and the unit vectors i and j as follows;
Dₓ = -155 sin 23° i + 0 j
The x-component of the vector is written as [tex]D_x = (-60.56 \ i + 0j)\ m[/tex].
The given parameters;
direction of the vector, θ = 23°magnitude of the vector, D = 155 mThe x-component of the vector is calculated as;
[tex]D_x = D \ \times sin\theta \\\\D_x = 155 \times sin(23)\\\\D_x = 60.56 \ m[/tex]
Since the direction of the vector is in negative x-axis, the x-component of the vectors is written as;
[tex]D_x = (-60.56 \ i + 0j)\ m[/tex]
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What is the minimum amount of energy required to completely melt a 7.25-kg lead brick which has a starting temperature of 18.0 °C? The melting point of lead is 328 °C. The specific heat capacity of lead is 128 J/(kg∙C°); and its latent heat of fusion is 23,200 J/kg.a. 1.68 × 105 J b. 2.88 × 105 J c. 4.56 × 105 J d. 5.96 × 105 J e. 7.44 × 105 J
Answer: c. 4.56 × 105 J
Explanation:
Given that
mass of lead brick, m= 7.25kg
Temperature T1 = 18.0 °C
Temperature T2 = 328 °C
specific heat capacity of lead, c = 128 J/(kg∙C°)
latent heat of fusion Lfusion =23,200 J/kg
Amount of energy Q =?
Using the formulae
Amount of energy ,Q =mc ( T2-T1)+ mLfusion
7.25kg x 128 J/(kg∙C°) x (328-18°C) + 7.25kg x 23200 J/kg
=455880J
=4.56 x 10^5 J
The minimum amount of energy required is 4.56 × 10^5 J.
Calculation of the minimum amount of energy:Since
mass of lead brick, m= 7.25kg
Temperature T1 = 18.0 °C
Temperature T2 = 328 °C
specific heat capacity of lead, c = 128 J/(kg∙C°)
latent heat of fusion =23,200 J/kg
So
we know that
Amount of energy ,Q =mc ( T2-T1)+ mLfusion
7.25kg x 128 J/(kg∙C°) x (328-18°C) + 7.25kg x 23200 J/kg
=455880J
=4.56 x 10^5 J
hence, The minimum amount of energy required is 4.56 × 10^5 J.
learn more about energy here; https://brainly.com/question/9676509
At which point in time does an object with the motion represented in the graph have an
instantaneous acceleration of -2 m/s^2?
Answer:
4s.
Explanation:
Hello,
In this case, considering that the instantaneous acceleration is computed via the change in the velocity divided by the change in the time, at 4 s we can evidence that the instantaneous acceleration is -2m/s² since the initial velocity at t=0s is 8m/s and at t=4s the velocity is 0 m/s, meaning that such decrease accounts for a deceleration process which is represented by a negative acceleration, and the value is:
[tex]a=\frac{0m/s-8m/s}{4s-0s}\\ \\a=-2m/s^2[/tex]
Best regards.
3. Does the Sun's light that reaches Earth produce a true continuous rainbow? If not, what colors
would you expect our sun's light to be missing if the outer atmosphere is pure Hydrogen?
Answer:
when there is no water in the atmosphere or when no drops are formed there is no rainbow..
he hydrogen transition lines would be missing in the visible range, the RED region
Explanation:
The sunlight that reaches the Earth is scattered by the atmosphere and radiated, as the atmosphere has mainly nitrogen, the radiated light is blue, this light does not produce a rainbow.
The sunlight must reach a drop of water that disperses the colors according to the refractive index of the water and in this way produces a rainbow, so when there is no water in the atmosphere or when no drops are formed there is no rainbow..
If the atmosphere were composed of Hydrogen, the hydrogen transition lines would be missing in the visible range, this corresponds to the so-called Balmer series and they are in the RED light region.
Two ropes are attached to a tree, and forces of F⃗ 1=2.0iˆ+4.0jˆN and F⃗ 2=3.0iˆ+6.0jˆN are applied. The forces are coplanar (in the same plane). (a) What is the resultant (net force) of these two force vectors? (b) Find the magnitude and direction of this net force.
Answer:
We can see that the 2 forces are being applied in the same direction
So the resultant force will be larger than the given forces
Resultant force = (2i + 4j) + (3i + 6j)
R = 5i + 10j
Magnitude of the resultant force :
R² = i² + j²
R² = 25 + 100
R = [tex]\sqrt{125}[/tex] = [tex]5\sqrt{5}[/tex]
Direction of the resultant force:
Tan Θ = Vertical component of force / Horizontal component of force
Tan Θ = 10 / 5
Tan Θ = 2
Θ = Arctan (2)
Θ = 63.4 degrees
Direction is 63.4 degrees in the NE direction
Kindly mark Brainliest
A) The resultant ( net force ) = 5i + 10 j
B) The magnitude and direction of this net force
magnitude of net force = 5√5 direction of net force = 63.4° NEGiven that :
The vector forces are coplanar ( In the same plane and direction )
A) resultant force = (2i + 4j) + (3i + 6j) = ( 2 + 3 ) i + ( 4 + 6 ) j
= ( 5 i + 10 j )
B ) Calculate The magnitude and direction of the net force
i) Magnitude of the force
R² = ( i² + j² )
= ( 5² + 10² )
= 25 + 100
∴ R = √ (25 + 100) = 5√5
ii) Determine the direction of resultant force
Tan ∅ = opposite / adjacent ( vertical force ( j ) / horizontal force ( i ) )
= 10 / 5 = 2
∅ = arctan ( 2 ) ≈ 63.4°
∴ direction of resultant force = 163.4° NE
Hence we can conclude that the resultant ( net force ) = 5i + 10 j and The magnitude and direction of this net force
magnitude of net force = 15 direction of net force = 1.107° NELearn more : https://brainly.com/question/24034108
Two trains, each having a speed of 33 km/h, are headed at each other on the same straight track. A bird that can fly 60 km/h flies off the front of on train when they are 60 km apart and heads directly for the other train. On reaching the other train, the (crazy) bird flies directly back to the first train, and so forth. What is the total distance the bird travels before the trains collide?
Answer:
66 km
Explanation:
Given that:
The speed of the two trains = 33 km/h
The speed of the bird = 60 km/h
The distance apart between the two trains = 60 km
From the given information, we are being told that the two trains are going at the same speed. Therefore, they will definitely collide at 30 km
We know that:
speed of the train = distance traveled × time
Making the time t the subject of the formula:
time = speed of the train / distance traveled
time = 30 km / 33 km/h
time = 0.909 / hr
Thus, the bird flying at a given speed of 60 km/h in a time of 0.909 / hr will cover a total distance of :
distance (d) = speed of the bird/ time
distance (d) = [tex]\dfrac{60 \ km/hr}{0.909 \ /hr}[/tex]
distance (d) = 66 km
100 POINTS.
PLEASE EXPLAIN YOUR ANSWER.
Explanation:
Draw free body diagrams for each mass.
There are 3 forces on the disk: weight force mg pulling down, normal force N pushing up, and tension force T pulling right.
There are 2 forces on the cylinder: tension force T pulling up and weight force 3mg pulling down.
Sum of forces on the disk in the centripetal direction:
∑F = ma
T = m v²/r
Sum of forces on the cylinder in the vertical direction:
∑F = ma
T − 3mg = 0
T = 3mg
Substituting:
3mg = m v²/r
3gr = v²
v = √(3gr)
Plug in values:
v = √(3 × 10 m/s² × 0.800 m)
v = √24 m/s
v ≈ 4.90 m/s
The energy stored in a wooden log transforms when the log is burned. Which of the following explanations BEST describes how the chemical energy stored in the log compares to the heat and light energy produced by burning?
A. chemical energy is the same and additional energy is produced as heat and light.
B. chemical energy is more than the amount of heat and light
C. the amount of chemical energy is less than the amount of heat and light energy
D. the amount of chemical energy equals the amount of heat and light energy.
Answer:
D. the amount of chemical energy equals the amount of heat and light energy.
Explanation:
Given that the first law of thermodynamics affirmed that energy is neither created nor destroyed however, it can be transformed from one form to another. In other words, while, during the transformation of energy, no energy is lost, the input energy is also equal to output energy.
Hence, the chemical energy stored in the log is EQUAL to the heat and light energy produced by burning.
Two planets, Dean and Sam, orbit the Sun. They each have with circular orbits, but orbit at different distances from the Sun. Dean orbits at a greater average distance than Sam. According to Kepler's Third Law, which planet will have a longer orbital period? Group of answer choices Dean Sam Since they both have circular orbits, they will have the same orbital periods. There isn't enough information to tell.
Answer:
The correct answer is Dean has a period greater than San
Explanation:
Kepler's third law is an application of Newton's second law where the force is the universal force of attraction for circular orbits, where it is obtained.
T² = (4π² / G M) r³
When applying this equation to our case, the planet with a greater orbit must have a greater period.
Consequently Dean must have a period greater than San which has the smallest orbit
The correct answer is Dean has a period greater than San
Answer:
According to the law of universal gravitation, any two objects are attracted to each other. The strength of the gravitational force depends on the masses of the objects and their distance from each other.
Many stars have planets around them. If there were no gravity attracting a planet to its star, the planet's motion would carry it away from the star. However, when this motion is balanced by the gravitational attraction to the star, the planet orbits the star.
Two solar systems each have a planet the same distance from the star. The planets have the same mass, but Planet A orbits a more massive star than Planet B.
Which of the following statements is true about the planets?
A.
Planet B will keep orbiting its star longer than Planet A.
B.
Planet A has a longer year than Planet B.
C.
Planet A orbits its star faster than Planet B.
D.
Planet B is more attracted to its star than Planet A.
Explanation:
What force causes oppositely charged particles to attract each other?
A. Magnetic force B. Compression
C. Electrical Force D. Gravity
Answer:
The electromagnetic force.
Answer:
It is electrical force
Explanation:
i got it wrong on A P E X with magnetic hope this helps!
7. Solve (3.96 x 10^2)/(1.6 x 10^-8). Be
sure your answer is in scientific notation.
Round to two decimal places.
(1 Point)
Enter your answer
Answer:
[tex]2.48*10^{10}[/tex]
Explanation:
Given the expression (3.96 x 10^2)/(1.6 x 10^-8), we are to express in scientific notation. Applying one of the laws of indices which says;
[tex]\frac{a^m}{a^n} = a^{m-n}[/tex]
The expression becomes;
[tex]= \dfrac{3.96}{1.6}*\dfrac{10^2}{10^{-8}}\\ \\= \dfrac{3.96}{1.6}*10^{2-(-8)}\\\\= \dfrac{3.96}{1.6}*10^{2+8}\\\\= \dfrac{3.96}{1.6}*10^{10}\\\\= 2.475*10^{10}\\\\= 2.48*10^{10} (to \ 2dp)[/tex]
How is a scientific law different than a scientific theory ?
Answer: scientific law is the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory
hope this helps
plz mark brainleist
Average speed is calculated by dividing the?
Explanation:
Hey there!
By dividing "total distance" by "time taken".
Reason: From formula.
[tex]average \: speed = \frac{total \: distance}{time \: taken} [/tex]
Hope it helps...
PLEASE HURRY!!!
WILL MARK!!!
Which statement describes a difference between the lower mantle and oceanic crust?
Answer:
Its C on edge
Explanation:
trust me
Emily wanted to see what battery lasted the longest. She put each battery into a clock and recorded the time that the clock stopped. She used Duracell, Energizer, Kroger brand, and EverReady. Iv,Dv, Control, consistent
Answer:
This question is asking to identify the following variables:
Independent variable (IV): Battery
Dependent variable (DV): Time the clock stopped
Constant: Same clock
Control: No stated control
Explanation:
The independent variable in an experiment is the variable that is subject to manipulation or change by the experimenter. In this experiment, the independent variable is the BATTERIES (Duracell, Energizer, Kroger brand, EverReady).
The dependent variable is the variable that responds to the changes made to the independent variable. It is the variable that the experimenter measures. In this case, the dependent variable is the TIME IT TAKES FOR THE CLOCK TO STOP.
Constants or control variable is the variable that the experimenter keeps constant or unchanged for all groups throughout the experiment in order not to influence the outcome of the experiment. The constant in this case is the SAME CLOCK USED.
Control group is the group that does not receive the experimental treatment or independent variable in an experiment. In this case, all groups received a different kind of battery.
in a closed system three objects have the following momentum: 11 kg* m/s, -65 kg*m/s and -100 kg m/s. the objects collide and move together. What is the total momentum after the collision? 55 kg*m/s 275 kg * m/s -55kg * m/s -275 kg m/2
Explanation:
The momentum of the three objects are as follow :
11 kg-m/s, -65 kg-m/s and -100 kg-m/s
Before collision, the momentum of the system is :
[tex]P_i=11+(-65)+(-100)\\\\P_i=-154\ kg-m/s[/tex]
After collison, they move together. It means it is a case of inelastic collision. In this type of collision, the momentum of the system remains conserved.
It would mean that, after collision, momentum of the system is equal to the initial momentum.
Hence, final momentum = -154 kg-m/s.
11. Angie runs around a circular track for 20mins. The track is 1km and she runs at a rate of
1km10min. What is her total displacement?
a. 2km counterclockwise
b. 0.1km
c. 2km clockwise
d. Okm
e. 2km
Answer:
0 km
Explanation:
Since she is running in a circle, her final position is where she started which is at 0 km.
0km is her total displacement. So, the correct option is (D).
What is Displacement?Displacement is described as a change in the position of an object which is a vector quantity and has a direction and a magnitude. It is represented as an arrow pointing from the starting position to the final position. For example- If an object moves from position A to position B, then the position of the object changes.
Displacement is defined as the shortest distance from the initial position to the final position of the object. For above given information, Angie is running in a circle, so her final position is where she started which is at 0 km.
Thus, 0km is her total displacement. So, the correct option is (D).
Learn more about Displacement, here:
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Which of the following are evidence of what happened in the past?
A.
volcanoes and plate movement
B.
weathering and rain
C.
weather and erosion
D.
earthquakes and climate
Answer:
A
Explanation:
volcanoes and plate movement
At a painfully loud concert, a 120-dB sound wave travels away from a loudspeaker at 343 m/s.
How much sound wave energy is contained in each 1.0-cm^3 volume of air in the region near this loudspeaker?
Answer:
2.9*10^-9 J
Explanation:
Given that sound level is B= 120dB
And B=10log(Io/I)
And I = (10^12)Io
So I = 1W/m²
So to find Energy
∆E= I∆V/v
Where ∆V= 1*10-6m³
v = 343
So ∆E=2.9*10^-9 J after substituting the values
3. Why do we revise laws?
Answer:
Everyone is held accountable to the same laws, and those laws protect our fundamental rights. This is the foundation of the rule of law in the United States. We need new laws because life and the world keep revolving and changing. We therefore need new laws to match the latest trending events in the country.
When a current of 0.015 A passes through human body at 240 volts p.d it
causes
Explanation:
Given that,
Current, I = 0.015 A
Voltage, V = 240 volts
We need to find the resistance. Using Ohm's law we can find it as follows :
[tex]V=IR\\\\R=\dfrac{V}{I}\\\\R=\dfrac{240}{0.015}\\\\R=16000\ \Omega[/tex]
So, When a current of 0.015 A passes through human body at 240 volts p.d it causes 16000 ohms of resistance.
Which figure shows vector A - vector B?
Answer:
The first and the last answer
What does the measurement unit N stand for?
Explanation:
The newton (symbol: N) is the International System of Units (SI) derived unit of force.
Answer:
The newton is the SI unit of force, and is the force which will accelerate one kilogram one metre per second squared. The symbol of the newton in SI is N. The newton is also the unit of weight
Explanation:
I hope it helps
A moving roller coaster speeds up with constant acceleration for 2.3\,\text{s}2.3s2, point, 3, start text, s, end text until it reaches a velocity of 35\,\dfrac{\text{m}}{\text{s}}35 s m 35, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction. During this time, the roller coaster travels 41\,\text{m}41m41, start text, m, end text. We want to find the initial velocity of the roller coaster before it starts to accelerate. Which kinematic formula would be most useful to solve for the target unknown?
Answer:
Δx=(v+v0/2)t
Explanation:
We can figure out which kinematic formula to use by choosing the formula that includes the known variables, plus the target unknown.
In this problem, the target unknown is the initial velocity v_0v
0
v, start subscript, 0, end subscript of the roller coaster.
