Answer:
STATIC friction acts on objects that are not moving........
Explanation:
DOES THIS HELPS!!
An astronaut weights 8x10^2
Answer:
800
Explanation:
10^2 = 100
8 x 100 = 800
Write two or three sentences to describe the conductivity of a conductor. Explain its conductivity in terms of the electrons in it.
The conductivity of a conductor refers to its ability to conduct electrical current.
A material that has high conductivity allows electrical charges to flow through it easily and with little resistance, while a material with low conductivity does not allow electrical charges to flow as easily and has more resistance.
The conductivity of a conductor is determined by the number of free electrons in the material, as well as how easily these electrons can move through the material.
In a conductor, the atoms are closely packed together and the electrons are not tightly bound to the atoms, allowing them to move freely through the material and carry an electrical charge. This facilitates the flow of electrical current through the material, resulting in high conductivity.
Learn more about conductors:
https://brainly.com/question/18084972
No links or viruses!
Which of the following are characteristics of noble gases?
A. They're highly reactive elements.
B. They're inert
C. They're found in Group 1.
D. They don't react with other elements.
Which of the following are characteristics of noble gases?
[tex]{ \bf{ \underbrace{Answer :}}}[/tex]
[tex]\sf\red{B. \:They're\: inert.}[/tex] ✅
An inert gas is one that does not undergo chemical reactions. The noble gases have complete outer shells, so they have no tendency to lose, gain, or share electrons. This is why they are said to be inert.[tex]\sf\purple{D.\: They \:don't \:react\: with\: other\: elements.}[/tex]✅
Noble gases are the least reactive of all elements. This is because they already have the desired eight total 's' and 'p' electrons in their outermost (highest) energy level.[tex]\circ \: \: { \underline{ \boxed{ \sf{ \color{green}{Happy\:learning.}}}}}∘[/tex]
If a runner has a speed of 8.66m/s and runs for 46.2s what distance is covered? tv = d
v=
d=
t=
Answer:
[tex]\text{Using the formula: }v=\frac{d}{t}\\\therefore vt=d\\\text{Plug and chug:}46.2(8.66)=400.092\text{ metres}[/tex]
Which of the following could be used as an INSULATOR?
a.) plastic plate
b.) silver spoon
c.) copper wire
d.) gold necklace
Answer:
Probably copper wire
Explanation:
I took the class and that's the only one that sounds right but I'm pretty dum lol
Two carts of equal mass are on a horizontal surface with negligible friction. Cart A is approaching cart B, which is at rest, as shown in Figure 1 above. Attached to cart B is a spring that is initially compressed. At the moment cart A collides with cart B, the spring is released and pushes on cart A, as shown in Figure 2 above. Which of the following correctly states what happens to the kinetic energy and the momentum of the two-cart system as a result of the collision compared to those quantities before the collision?
(A) Kinetic energy: Increases; Magnitude of Momentum: Decreases
(B) Kinetic energy: Increases; Magnitude of Momentum: Stays the same
(C) Kinetic energy: Increases; Magnitude of Momentum: Increases
(D) Kinetic energy: Stays the same; Magnitude of Momentum: Decreases
(E) Kinetic energy: Stays the same; Magnitude of Momentum: Stays the same
The option that correctly states what happen to the kinetic energy and the momentum of the two-cart system as a result of the collision compared to those quantities before the collision is
B) Kinetic energy: Increases; Magnitude of Momentum: Stays the same
What is kinetic energy?The energy an object has as a result of motion is known as kinetic energy. A force must be applied to an object in order to accelerate it. We must put in effort in order to apply a force.
Since the elastic potential energy that was initially stored in the compressed spring has now been converted into kinetic energy, the system's total energy should be conserved. As a result, the system's kinetic energy increases. As a result, the system's kinetic energy rises.
The magnitude of the two-cart system's net momentum remains constant because there is no outside force acting on it, which implies that the system's overall momentum should be conserved.
Therefore, the correct option is B.
Learn more about energy on:
https://brainly.com/question/25959744
#SPJ1
A point charge Q moves on the x-axis in the positive direction with a speed of 370 m/s. A point P is on the y-axis at y = + 80 mm. The magnetic field produced at point P, as the charge moves through the origin, is equal to - 0.8 μT k^. When the charge is at x = + 40 mm, what is the magnitude of the magnetic field at point P? (μ0 = 4π × 10-7 T • m/A)
A. 0.57 μT
B. 1.1 μT
C. 0.92 μT
D. 0.74 μT
Answer:
The answer is C:
Explanation:
HOPE IT HELPS!!
Which one of the following statements about velocity is true?
O Velocity is the magnitude of speed.
O Velocity is the displacement of an object divided by the time interval.
O Velocity describes how fast an object is changing speed.
O Speed and velocity refer to the same vector quantity.
Answer:
Velocity is the displacement of an object divided by the time interval.
Explanation:
Let's consider each choices:
1. Velocity is not the magnitude of speed. Velocity is a vector quantity which means it consists of both direction and magnitude. Speed is the magnitude of velocity, not the other way around.
3. Velocity describes how fast an object is changing speed. If a speed changes each time interval, that is not a velocity but rather the magnitude of acceleration. Magnitude of acceleration is change in speed over time. Acceleration is the one that describes how velocity is changing through time.
4. Speed and velocity refer to the same vector quantity. Speed is not a vector quantity but a scalar quantity which only has magnitude. Speed is also considered as the magnitude of velocity as well.
Therefore, the only correct choice is 2. Velocity is the displacement of an object divided by the time interval. This is true since velocity is change in position (displacement) over time.
What causes the poles of the electromagnet in an audio speaker to repeatedly switch directions?
a metal striker that pulls on the magnet
a diaphragm that vibrates around the magnet
a current that rapidly switches direction
a device that opens and closes a circuit
Answer:
he is right its c
Explanation:
Answer:
a current that rapidly switches direction
Explanation:
the work a force does is measured in?
Explanation:
work a force is measured in newton-meters (N-m)
[tex] \huge \hookrightarrow \mathfrak{ \green{Answer}}[/tex]
we know,
[tex] \boxed{ \small{workdone = force \times displacement}}[/tex]
[tex]\longmapsto \: work \: done = N \times m[/tex]
[tex]work \: \: done \: \: is \: \: measured \: \: in \: \: \boxed {\color{gold}{Nm}}[/tex]
Nm = Newton meter
An ice-making machine inside a refrigerator operates in a Carnot cycle. It takes heat from liquid water at 0.0 degrees Celsius and rejects heat to a room at a temperature of 20.6 degrees Celsius. Suppose that liquid water with a mass of 82.1 kg at 0.0 degrees Celsius is converted to ice at the same temperature. Take the heat of fusion for water to be Lf=3.34×105 J/kg.
A. How much heat |QH| is rejected to the room?
B. How much energy E must be supplied to the device?
Answer:
A. Q = 2.74 x 10⁷ J = 27.4 MJ
B. E = 3.91 x 10⁸ J = 391 MJ
Explanation:
A.
Heat rejected can be found as follows:
[tex]Q = mL[/tex]
where,
Q = Heat rejected = ?
m = mass = 82.1 kg
L = Latent Heat of fusion = 334000 J/kg
Therefore,
[tex]Q = (82.1\ kg)(334000\ J/kg)[/tex]
Q = 2.74 x 10⁷ J = 27.4 MJ
B.
First, we will calculate the efficiency of the Carnot Cycle as follows:
[tex]Efficiency = 1-\frac{T_1}{T_2}[/tex]
where,
T₁ = Heat intake temperature = 0°C + 273 = 273 k
T₂ = Heat rejection temperature = 20.6°C + 273 = 293.6 k
Therefore,
[tex]Efficiency = 1 - \frac{273\ k}{293.6\ k} \\\\Effciency = 0.07[/tex]
Therefore, the energy input required is:
[tex]Efficiency = \frac{Q}{E}\\\\E = \frac{Q}{Efficiency} = \frac{2.74\ x\ 10^7\ J}{0.07}[/tex]
E = 3.91 x 10⁸ J = 391 MJ
An astronaut has two springs: Spring A and Spring B. She also has two metal blocks that she can hang from the springs: Block X and Block Y. At her lab in Orlando, Florida, she hangs Block X from Spring A and sees that Spring A stretches 2.04 cm as a result. Later, at a research station on the moon, she hangs block X from spring A and finds that Spring A only stretches 0.34 cm. Then (still on the moon) she hangs block Y from Spring A and sees that spring A stretches 0.54 cm.
1) How much would spring A stretch if Block Y were hanging from it back in the lab in Orlando?
2) On the moon, when Block Y is hanging from Spring B, Spring B stretches a distance of 1.3 cm. In Orlando, how much would Spring B stretch when Block X is hanging from it?
Answer:
Explanation:
Let the spring constant of spring A and B be k₁ and k₂ . Mass of box X and Y be m₁ and m₂ .
Force created in spring which is stretched by d is kd where k is spring constant .
At her lab in Orlando, Florida,
k₁ x .0204 m = m₁ g where g is acceleration due to earth's gravity
k₁ = 49 m₁ g
At a research station on the moon
k₁ x .34 x 10⁻² m = m₁ g₁ where g₁ is acceleration due to gravity at moon
k₁ = 294 .11 m₁ g₁
49 m₁ g = 294 .11 m₁ g₁
g = 6.0022 g₁
At a research station on the moon
k₁ x .54 x 10⁻² m = m₂ g₁
k₁ = 185.18 m₂ g₁
294 .11 m₁ g₁ = 185.18 m₂ g₁
1.588 m₁ = m₂
1 )
At her lab in Orlando, Florida,
k₁ x d = m₂ g , where d is the new stretch that is to be calculated .
185.18 m₂ g₁ d =m₂ g
185.18 d g₁ = g
185.18 d g₁ = 6.0022 g₁
d = .03241 m
= 3.24 cm .
2 )
At a research station on the moon
when Block Y is hanging from Spring B
k₂ x .013 = m₂ g₁
k₂ = 76.92 m₂ g₁
At her lab in Orlando, Florida,
Spring B stretch when Block X is hanging from it
k₂ d₁ = m₁ g
76.92 m₂ g₁ d₁ = m₁ g
76.92 m₂ g₁ d₁ = m₁ 6.0022 g₁
76.92 m₂ d₁ = m₁ 6.0022
12.815 x 1.588 m₁ x d₁ = m₁
d₁ = .049 m
= 4.9 cm .
In this exercise we have to use the knowledge of springs to calculate the distance from it, that way:
A)d=3.24 cm
B)d=4.9 cm
So, before starting the calculations, we have to organize the values and put everything in function of a single unknown such as:
[tex]k_1 * 0.34 * 10^{-2} m = m_1 g_1\\ k_1 = 294 .11 m_1 g_1\\49 m_1 g = 294 .11 m_1 g_1\\g = 6.0022 g_1\\k_1 *0 .54 * 10^{-2} m = m_2 g_1\\k_1 = 185.18 m_2 g_1\\294 .11 m_1 g_1 = 185.18 m_2 g_1\\1.588 m_1 = m_2[/tex]
A) By calculating the distance we find that:
[tex]k1_1 * d = m_2 g\\185.18 m_2 g_1 d =m_2 g\\185.18 d g_1 = g\\185.18 d g_1 = 6.0022 g_1\\d = 0.03241 m= 3.24 cm[/tex]
B) So now calculating the distance from the lab to the moon, so:
[tex]k_2* 0.013 = m_2 g_1\\k_2 = 76.92 m_2 g_1\\k_2 d_1 = m_1 g\\76.92 m_2 g_1 d_1 = m_1 g\\76.92 m_2 g_1 d_1 = m_16.0022 g_1\\76.92 m_2 d_1 = m_1 6.0022\\12.815 * 1.588 m_1 * d_1= m_1\\d_1 = 0.049 m = 4.9 cm[/tex]
See more about springs at brainly.com/question/4433395
Which type of material uses the subtractive coloring process?
a. light
b. math
c. opaque
d. pigments
e. none of these
draw diagram of how a reflecting telescope works. show how the angles of reflection would work with mirrors placed at 2 different angles
Lenses, which are pieces of curved, clear glass, were employed in early telescopes to focus light.
What is Telescope?Curved mirrors are used by the majority of telescopes nowadays to collect light from the night sky. Light is focused by a telescope's mirror or lens' shape.
Astronomers use a telescope to observe distant things. Curved mirrors are used by the majority of telescopes, including all large telescopes, to collect and concentrate light from the night sky.
The original telescopes employed lenses, which are simply curved pieces of clear glass, to focus light. The "optics" of a telescope are the mirrors or lenses. Strong telescopes may view objects that are extremely faint and incredibly far away.
Therefore, Lenses, which are pieces of curved, clear glass, were employed in early telescopes to focus light.
To learn more about Telescope, refer to the link:
https://brainly.com/question/556195
#SPJ1
A 5,257 kg rocket blasts off to the moon with an acceleration of 76 m/s ^2 what is the net force on the rocket
Newton's subsequent law expresses that power is corresponding to what exactly is needed for an object of consistent mass to change its speed. This is equivalent to that item's mass increased by its speed increase.
We use Newtons, kilograms, and meters each second squared as our default units, albeit any proper units for mass (grams, ounces, and so forth) or speed (miles each hour out of every second, millimeters per second², and so on) could unquestionably be utilized also - the estimation is the equivalent notwithstanding.
Hence, the appropriate answer will be 399,532.
Net Force = 399532
Describe the role of the teacher and the learner in a natural science and technology classroom
Students are instructed in subject-specific classes by science professors. They develop lesson plans, assess student performance, and educate using lectures, technology.
What are the characteristics of a good teacher?The teacher who gives their best in order to develop the skills in all student of their class. A good teacher has to be a great command of his/her subjects.
He/she has to put their effort to improve the weak student of the class as well must appreciate the effort of good students.
The role of the teacher and the learner in a natural science and technology classroom is;
Students are instructed in subject-specific classes by science professors. They develop lesson plans, assess student performance, and educate using lectures, technology,
They also serve as role models for anticipated conduct in order to develop and maintain an ordered, disciplined classroom.
They must also be analytical since they must analyze kids' development and modify lesson plans for special-needs children.
They may create and sustain interpersonal ties with students, parents, other staff members, and administrators.
Hence the role teacher is to instruct the student, maintain discipline and educate using technology.
To learn more about the teacher refer to the link;
https://brainly.com/question/10283004
1. At a location in Europe, it is necessary to supply 1000 kW of 60-Hz power. Only power sources available operate at 50 Hz. It is decided to generate the power by means of a motor-generator set consisting of a 20- pole synchronous motor (its electrical rotating frequency is 50 Hz) driving a synchronous generator. How many poles should the synchronous generator have in order to convert 50-Hz power to 60-Hz power
Answer:
Explanation:
From the given information:
The speed of a synchronous motor in relation to its frequency can be represented with the formula:
[tex]n_{sm}= \dfrac{120f_{se}}{P}[/tex]
where,
the electrical frequency [tex]f_{se}[/tex] is measured in Hz
the number of poles = P
For us to estimate the number of poles to have 50 Hz - 60 Hz Power, then we need to relate the frequencies of the above equation.
i.e
[tex]\dfrac{120(50 \ Hz)}{P_1}= \dfrac{120( 60 \Hz)}{P_2} \\ \\ \dfrac{6000 \ Hz}{P_1}= \dfrac{7200 \ Hz}{P_2} \\ \\ \dfrac{P_2}{P_1}=\dfrac{7200}{6000} \\ \\ \\ \dfrac{P_2}{P_1}= \dfrac{12}{10}[/tex]
Thus, we can conclude that 10 poles synchronous motor is attached with 12 poles synchronous generator in order to convert 50 Hz to 60 Hz power.
Chromatic aberration occurs when:___.
a. a mirror does not focus all colors of light to the same place.
b. a lens does not focus all colors of light to the same place.
c. the absorption of blue light by an intervening dust cloud causes a star to look redder than it really is.
d. atmospheric scattering causes the Sun to look red at sunset.
Answer:
b. a lens does not focus all colors of light to the same place.
Explanation:
Chromatic aberration is a defect of a lens. In this defect, the lens is unable to focus the different wavelengths of the light on a single focal point. It is also known as chromatic distortion and color fringing. It is caused by the dispersion of light while passing through a lens. As a result, the image might become blurred and different colors are observed around its edges. It can be corrected by the use of a combination of converging and diverging lenses.
Hence, the correct option will be:
b. a lens does not focus all colors of light to the same place.
A 2.0-kg laptop sits on the horizontal surface of the seat of a car moving at 8.0 m/s. The driver starts slowing down to stop. Find the minimum stopping distance so the computer does not slip and fall onto the floor if the coefficient of static friction between the seat and the laptop is 0.40 and the coefficient of kinetic friction is 0.20.
Answer: [tex]32.65\ m[/tex]
Explanation:
Given
mass of laptop m=2 kg
The velocity of car u=8 m/s
The coefficient of static friction is [tex]\mu_s=0.4[/tex]
The coefficient of kinetic friction is [tex]\mu_k=0.2[/tex]
As the car is moving, so the coefficient of kinetic friction comes into play
deceleration offered by friction [tex]\mu_kg=0.2\times 9.8\ m/s^2[/tex]
Using the equation of motion [tex]v^2-u^2=2as\\[/tex]
insert the values
[tex]0^2-8^2=2(-0.2\times 9.8)s\\\\s=\dfrac{64}{1.96}\\\\s=32.65\ m[/tex]
Hi can anyone please help me with this question? i just cant seem to do it.. Thanksss
Newtons Universal Gravitational Law.
Bill gates a billionaire and space-X CEO, send Robin, 65kg, to planet Gidz. Gidz has a very weak gravitational attraction, of 1.56 N/Kg. Planet GIdz has a radius of 6.35 x 10^11 m.
i. determine the mass of planet Gidz.
Answer:
F = G M m / R^2 = m a
G M / R^2 = a
M = a R^2 / G
M = 1.56 N/kg * 6.35 m^2 / 6.67E10-11 N-m^2 / kg^2
M = 1.56 * 6.35 / 6.67E-11 kg
M = 1.49 * 10^11 kg
a car with mass m1=1000kg moving at speed v1=6m/s hits a stationary truck with mass m2=5000kg. The impact is absolutely inelastic. Determine the speed of both car and truck immediately after the impact
Impact Speed means the maximum speed of impact tested upon the bumper of the vehicle pursuant to sections 581.6 and 581.7 of part 581 of title 49 of the Code of Federal Regulations.
In an inelastic collision, what occurs when two objects collide?An inelastic collision occurs when items cling together after impact and kinetic energy is not preserved. Because of this violation of conservation, the forces between colliding objects may convert kinetic energy to other types of energy, such as potential energy or thermal energy.To calculate the momentum of either individual vehicle, divide the total system momentum by two (approx. 11 200 kg*m/s). Once the momentum of the individual automobiles is known, the after-collision velocity may be calculated by simply dividing momentum by mass (v=p/m).To learn more about impact speed to refer:
https://brainly.com/question/15695646
#SPJ1
A 42 kg cart is pushed forward with a total force of 225 Newtons. What is the work done if the cart moves forward 12 meters
Important Formulas:
[tex]w=Fd[/tex]
work(measured in joules) = force(measured in newtons) * distance(measured in meters)
__________________________________________________________
Given:
[tex]m=42kg[/tex]
[tex]F=225N[/tex]
[tex]d=12m[/tex]
[tex]w=Fd[/tex]
__________________________________________________________
Finding work:
[tex]w=Fd[/tex]
[tex]w=225\times12[/tex]
__________________________________________________________
[tex]\fbox{w = 2700 Joules}[/tex]
Can you help me with this question
A bar magnet's magnetic field lines flow from its north pole toward its south pole, just like they do in all magnets. Field lines that begin close to a pole's edges stay nearby the bar magnet longer than those that begin closer to the pole's centre.
What produces a magnetic field in a bar magnet?Because the molecules in magnets are arranged so that their electrons spin in the same direction, magnets are unique. This configuration and motion produces a magnetic force that emanates from a north- and south-seeking pole, respectively.
Where does a bar magnet's magnetic field are strongest?At the poles, it is strongest.
To know more about magnetic field visit:-
brainly.com/question/14848188
#SPJ1
2. How much work is done in lifting 214kg from the floor to a shelf at a height of 6m?
Answer:
12583.2 J or 12.5832 KJ
Explanation:
Work done can be expressed as force multiplied by displacement, or
W = Fs
In this case, we can calculate the force by using F = mg.
m is the mass, 214 kg, and g is gravitational acceleration, which is 9.8 m/s/s.
So, we Calculate 214 * 9.8 to get 2097.2
The displacement is 6m.
So, by doing W = Fs, we get
2097.2 * 6 = 12583.2 Joules
Drag and drop the terms at the left to match the appropriate descriptions at the right. ResetHelp Visual acuity Emmetropia Accommodation Astigmatism Myopia Hyperopia Presbyopia Refraction : normal vision. : reduction in visual acuity due to irregularities in the cornea or lens. : farsightedness. : nearsightedness. : age-related farsightedness due to loss of elasticity in the lens. : sharpness of vision. : bending of light rays. : changes the shape of the eye lens to focus light on the retina.
Answer: Visual acuity: sharpness of vision.
Myopia: nearsightedness
Refraction: bending of light rays.
Emmetropia: normal vision.
Accommodation: changes the shape of the eye lens to focus light on the retina.
Presbyopia: age-related farsightedness due to loss of elasticity in the lens.
Astigmatism: reduction in visual acuity due to changes in the cornea or lens.
Hyperopia: farsightedness
Myopia and hyperopia are refractive errors of the eye.
Presbyopia occurs in old age people.
Explanation:
Visual acuity: It can be defined as the inability to observe the details of shape of the object. Person loses sharpness in vision.
Myopia: It is a defect in vision in which person is able to observe the near by objects clearly but not able to see the distant objects.
Refraction: It can be defined as the bending of beam of light when it passes through from one substance to another.
Emmetropia: It is a vision without any defect.
Accommodation: It is the ability of the eye to adjust its focal length and adjusting the light on focus.
Presbyopia: It can be defined as the loss of ability of eye to focus on the object. It occurs in old age.
Astigmatism: It is a refractive error in which the eye does not focus light on retina.
Hyperopia: It is also called as farsightedness. Distant objects can be seen clearly but nearby appears blurry.
The weight of an object changed if the force of gravity changes? True or false
Answer:
True. If you bring a bowling ball away from earth it would weigh less because the less gravity pushing down on it.
Answer:
f
Explanation:
What's the difference between shunt and multiplier?
Answer:
A Shunt is a passive element, usually resistive, that is used to bypass current around another element, like a meter, that is not able to handle the full current flow. ... A Multiplier is an active element that amplifies a voltage or current to enable a less sensitive device or circuit to make use of it.
A Shunt which is a passive element resistive used to bypass current around another element, like a meter whereas A Multiplier which is an active element that amplifies a voltage or current to a less sensitive device
What is shunt ?The shunt can defined as it is generated by a resistor with an extremely low resistance that is coupled in parallel associated with some other resistor; A resistance of a shunt could be used just to increase the frequency of an ammeter measurement.
one of the example is The galvanometer employs a shunt to measure huge currents, can be also used as diode. some of the major Uses of shunt are used to determine big currents in galvanometers.
Shunt can safeguards the circuit where it is linked in parallel to the galvanometer in a circuit and act as an ammeter and the Current should be measured.
For more details shunt, visit
https://brainly.com/question/15074025
#SPJ2
What does flowing electrical charge produce?
Lightning.
Unusable energy.
Useable energy, electricity.
Global warming.
Answer:
Useable energy, electricity
5. If a jump rope is shaken fast enough to produce a wave with a wavelength of 0.5 m and
the crest of the wave passes a specific point 6 times per second, what is the velocity of the
wave?
Answer:
After solving the equation the wave is traveling at a velocity of 3 m/s.
What is velocity?Velocity is a vector quantity that describes the rate at which an object changes its position. It is a measure of both the speed and the direction of an object. Velocity is typically expressed in terms of meters per second (m/s). When an object is in uniform motion, its velocity is constant, meaning that it is not changing in magnitude or direction. If an object is accelerating, its velocity is changing over time, either in magnitude, direction, or both.
The velocity of the wave can be calculated using the following equation:
Velocity = Wavelength x Frequency
In this case, the wavelength is 0.5 m and the frequency is 6 Hz (6 cycles per second). So, the velocity of the wave is:
Velocity = 0.5 m x 6 Hz = 3 m/s
This means that the wave is traveling at a velocity of 3 m/s.
To learn more about velocity
https://brainly.com/question/29223620
#SPJ1
Cart A with a mass of 28kg is moving to the RIGHT at 11m/s and Cart B with a mass of 17kg is moving LEFT at negative 9m/s. The carts collide and STICK TOGETHER. What is the velocity of the carts after they collide?
Answer:
Should be 17.8m/s
Explanation:
Initial momentum = Final momentum
(m1×v1)+(m2×v2)=(m1+m2)v since its an inelastic collision.