Answer:
C
Explanation:
help? :(
A 9,300 kg. a railroad car traveling at a velocity of 15m/s strikes a second boxcar at rest. If the two cars stick together and move off with a velocity of 6m/s, what is the mass of the second car?
Answer:
m2 = 13950 [kg]
Explanation:
To solve this problem we must use the principle of conservation of linear momentum, which is defined as the product of mass by velocity, and can be determined by means of the following expression:
P = m*v
where:
P = lineal momentum [kg*m/s]
m = mass [kg]
v = velocity [m/s]
Now that momentum is conserved, we need to analyze the conditions before the collision and after the collision. In this way we must propose the following equation:
ΣPbefore = ΣPafter
(m1*v1) + (m2*v2) = (m1+m2)*v3
where:
m1 = mass of the railroad car = 9300 [kg]
v1 = velocity of the railroad car before the collision = 15 [m/s]
m2 = mass of the box car [kg]
v2 = velocity of the boxcar before the collision = 0 (the car is at rest)
(m1 + m2) = combined mass of the cars, they stick together after the collision [kg]
v3 = combined velocity of the cars after the collision = 6 [m/s]
(9300*15) + (m2*0) = (m1+m2)*6
139500 = (6*9300) + 6*m2
83700 = 6*m2
m2 = 13950 [kg]
The mass of the second railroad car which was initially at rest is 13950kg.
Given the data in the question;
Mass of railroad car1; [tex]m_1 = 9300kg[/tex]Initial velocity of railroad car1; [tex]u_1 = 15m/s[/tex]Mass of railroad car2; [tex]m_2 = \ ?[/tex]
Since railroad car2 was initially at rest,
Initial velocity of railroad car1; [tex]u_2 = 0[/tex]After the strike, the wo cars stick together and moved
Final velocity of both railroad car1 and 2; [tex]v = 6m/s[/tex]To determine the mass of the second railroad car, we use conservation of linear momentum:
[tex]m_1u_1 + m_2u_2 = (m_1 + m_2 )v[/tex]
We substitute our given values into the equation
[tex](9300kg * 15m/s) + ( m_2 * 0 ) = ( 9300kg + m_2 )6m/s\\\\9300kg * 15m/s = ( 9300kg + m_2 )6m/s\\\\139500kg.m/s = 55800kg.m/s + ( m_2 * 6m/s )\\\\139500kg.m/s - 55800kg.m/s = m_2 * 6m/s\\\\83700kg.m/s = m_2 * 6m/s\\\\m_2 = \frac{83700kg.m/s}{6m/s} \\\\m_2 = 13950kg[/tex]
Therefore, the mass of the second railroad car which was initially at rest is 13950kg.
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PLEASE HELP!!! a skateboard rolls down a ramp, starting from rest. after 3seconds, the skateboard’s velocity is 15m/s. what is the acceleration of the skateboarder?
The density of the Earth is greater than the density of an equal volume of water by _____.
5½ times
3½ times
1½ times
7½ times
Answer:
I think the second option is correct
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Tyler traveled 36 km at a speed of 8 km/hr. Mark traveled 48 km at a speed of 10 km/hr. Who traveled the fastest? Who got to their destination first?
Answer:
Tyler got to his destination first. It took him 4.5 hours
Explanation:
Tyler's trip: 36 / 8 = 4.5 hrs
Mark's trip: 48 / 10 = 4.8 hrs
From the frame of reference of car 2, what is the velocity of car
If the distance of an object is determined from the relation: d = a X + b Y Where: (d) is the distance covered by the body. (a) is a physical quantity which has a dimensions (L T^-1). (b) Is a physical quantity which has a dimensions (L T^-2). So: *
The dimension formula of (X) is T and that of (Y) is T^2.
The dimension formula of (X) is T and that of (Y) is T^-2
The dimension formula of (X) is T^-1 and that of (Y) is T^2.
The dimension formula of (X) is T^-1 and that of (Y) is T^-2.
Answer:
The dimension formula of X is T and that of Y is T^2
Explanation:
d = aX + bY is ACTAULLY [tex]S = V_{i} t + \frac{1}{2} a t^{2}[/tex]
so v = LT^-1
t = T
numerics do not have any dimensional formula so ignore [tex]\frac{1}{2}[/tex]
a = LT^-2
t = T^2
So answer for x is T and y T^2
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
Answer:
Explanation:
D Distance and Mass
Help with this review pls!!
Answer:
The 2 forces are a Push and a Pull
Mass is the resistance of change in speed or position when adding force.
Weight is the force of gravity
Tension Force is the pulling force transmitted through a string cable or chain. The formula for this is T = mg + ma.
It gives the particle the same acceleration as all those actual forces together as described by the Newton's second law of motion.
An unbalanced force is when there is 2 forces on opposites of an object both are adding force but one side is stronger than the other.
Friction is a force that heats things up. This happens when we rub our hands together and the heat that is generated from the friction makes our hands warmer.
Static friction is what keeps the box from moving without being pushed, and it must be overcome with a sufficient opposing force before the box will move. Kinetic friction (also referred to as dynamic friction) is the force that resists the relative movement of the surfaces once they're in motion.
HELP!!!
In the "Monster study," what did psychologists tell the group of orphans who did not suffer from stuttering?
A.
They were told that they weren’t really stutterers.
B.
They were told that they had very severe cases of stuttering.
C.
They were told that stuttering could be overcome with practice.
D.
They were told that their parents were responsible for their stuttering.
Please select the best answer from the choices provided
A
B
C
D
Answer:
They were told that they had very severe cases of stuttering.
Explanation:
The monster study conducted in 1939 was a certain stuttering experiment that was done by Wendell Johnson on 22 Orphan at the University of Iowa, United States. Eleven of the children got positive speech therapy while the other half was seen to have negative speech therapy which belittled them for their speech imperfections.
The experiment was called monster because many people were horrified that such experiments could be done on children who were orphans.
B. They were told that they had very severe cases of stuttering.
The Monster Study was conducted by Dr. Wendell Johnson to learn more about why children developed a stutter and to see if stuttering was a result of learned behavior. However, there are several ethical problems with the the Monster study.
In this study, psychologists tell the group of orphans who did not suffer from stuttering that they had very severe cases of stuttering.
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Consider a box sliding down horizontally across a straight line. Which of the following factors affects the amount of work done against friction in this situation?
A. Speed of the box
B. Time taken to move the box
C. Distance the box is moved
D. Direction of the box is moved
Answer:
uhhh speed of box??? I think
The factor affecting the amount of work done against friction is the distance traveled by the box.
The work done against friction is energy dissipated in reducing frictional force along the horizontal surface.
The magnitude of the work done in reducing the frictional force along the horizontal surface is given as;
W = μFd
where;
μ is the coefficient of frictionF is applied horizontal forced is the horizontal distance traveled by the boxThus, we can conclude that the factor affecting the amount of work done against friction is the distance traveled by the box.
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Which of the following is true about the speed of light?
A: it is a constant when the light is traveling in a vacuum
B:it speeds up or slows down depending on the observer
C: it’s slowest in a vacuum
D:it varies depending on the color of the light.
Answer:
C. it’s slowest in a vacuum
Explanation:
When light propagates through a material, it travels slower than the vacuum speed, c.
Answer:
A
Explanation:
I took the test
Both the X- and Y-components of a vector are doubled. Which of the following describes what happens to the resulting Vector?
a) Magnitude increases by √(2
b) Magnitude increases by √(2, and the direction changes
c) Magnitude increases by 2
d) Magnitude increases by 2, and the direction changes
Answer: C. Magnitude increases by 2
Explanation:
If the magnitudes of X and Y vectors are increased, then the resultant vector will increase by a factor of 2 but the direction does not changes. Hence, option c is correct.
What is a vector ?A vector is a physical quantity having both magnitude and direction. For example, force, velocity, work done, momentum, velocity etc. are vector quantities. The quantities which does not have direction are called scalar quantity.
The resultant vector R of vectors in X and Y direction can be written as follows:
[tex]\rm R = \sqrt{x^{2} + y^{2}}[/tex]
If the x and y components are doubled to 2x and 2y then the resultant vector becomes,
[tex]\rm R = \sqrt{(2x)^{2} + (2y)^{2}}\\\\ R = \sqrt{4 (x^{2} + y^{2})\\\\\\ R = 2 \sqrt{x^{2} + y^{2} \\ \\ \\ \\[/tex]= 2R
Therefore, the resultant vector will increases by 2 times. However the direction will not change. Hence, option c is correct.
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As the cloud passes over the building, a lightning strike occurs and a charge of 0.84C flows through the lightning conductor. The charge flows for 3.5 × 10^-5 s.
Calculate the average current in the lightning conductor during this time. State the formula used in your answer
Answer:
I=24,000 Amp
Explanation:
Electric Current
Is a measure of the quantity of charge Q flowing by a point in a time period of t.
The standard metric unit for the current is the Ampere, often abbreviated as Amps or A.
It can be calculated as:
[tex]\displaystyle I=\frac{Q}{t}[/tex]
The cloud generates a lightning strike that releases a charge Q=0.84 C during a time [tex]t=3.5\cdot 10^{-5}\ sec[/tex].
The current is of course, not of a constant value, but an average value can be calculated by using the above formula:
[tex]\displaystyle I=\frac{0.84}{3.5\cdot 10^{-5}}[/tex]
[tex]\boxed{I=24,000\ Amp}[/tex]
Which particle is used as a beam to treat cancer? electron neutron proton
Answer:neutron
Explanation:
Because it is similar to the motor neurons
Answer:
Proton
Explanation:
Proton therapy, also called proton beam therapy, is a type of radiation therapy. It uses protons rather than x-rays to treat cancer. A proton is a positively charged particle. At high energy, protons can destroy cancer cells.
An escaped convict runs 1.70 km due East of the prison. He then runs due North to a friend's house. If the magnitude of the convict's total displacement vector is 2.50 km, what is the direction of his total displacement vector with respect to due East?
Answer:
The right approach will be "47° north of east".
Explanation:
The given values are:
East of prison
= 1.70 km
Displacement vector
= 2.50 km
Now,
The direction will be:
⇒ [tex]Cos \ \theta =\frac{1.7}{2.5}[/tex]
⇒ [tex]=0.68[/tex]
⇒ [tex]\theta=47.16^{\circ}[/tex]
i,e., [tex]\theta = 47^{\circ}[/tex] (north of east)
The direction of his total displacement vector with respect to due East is 1.83km
Resultant vectorGiven the following parameters
Distance ran through east = 1.70km
displacement = 2.50km
Required
Total displacement vector with respect to due north
Using the expression below;
d = √x² + y²
2.5² = 1.7² + y²
y² = 2.5² - 1.7²
y² = 3.36
y = 1.83km
Hence the direction of his total displacement vector with respect to due East is 1.83km
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Using Newton's First Law, predict what will happen when a car traveling on an icy road approaches a sharp turn
O The car will come to a complete stop without sliding
O The car will continue to travel in a straight line
O The car will be able to turn without difficulty
O The car will accelerate forward
Answer:
i need the answer broo i am sooo koko
Explanation:
dsfedaes
PHYSICS HELP PLEASE ONE QUESTION 10 POINTS:)
Case 1 has the greatest strength for the push and pull. Option A is correct.
What is force?The pushes and pulls the body experiences are referred to as force. It can occasionally be used to alter the body's size, shape, and direction.
Mass times acceleration equals force, according to the definition. Newton is its measure.
The force transmitted through a rope, string, or wire as it is tugged by opposing forces is referred to as the tension force.
Energy is drawn equally from both ends by the tension force, which is exerted along the whole length of the wire.
The tension force is acting in the rope causing greater strength for the push and pull.
Hence, option A ia correct.
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how do you find displacement
Answer:
Displacement can be calculated by measuring the final distance away from a point, and then subtracting the initial distance. Displacement is key when determining velocity (which is also a vector). Velocity = displacement/time whereas speed is distance/time. I hope it helped. Please give brainliest
Explanation:
Which best summarizes a concept related to the work-energy theorem?
When work is positive, the environment does work on an object.
When work is negative, the environment does work on an object.
O When work is positive, the kinetic energy in a system remains constant.
When work is negative, the kinetic energy in a system remains constant.
Answer: When work is positive, the environment does work on an object
Explanation:
The correct option is a)When work is positive, the environment does work on an object.
What is positive and negative work done ?
If work is done on the system , positive work is done on the system because energy enters the system in case of positive work done .If work is done by the system , work done will be negative
According to work energy theorem , change in kinetic energy is equal to work done . when energy enters in the system that means final energy is greater than the initial energy of the system , which implies positive work is done on an object .
this implies , correct option is a)When work is positive, the environment does work on an object.
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How is Impulse related to Force?
ice floats in water. which must be true. A. Ice molecules have more mass than water molecules. B. Ice molecules have less mass than water molecules. C. A volume of ice has less mass than the same volume of water. D. one gram of ice has less volume than 1 g of water.
Answer:
B
Explanation:
As we all know,mass is the amount of substance a body contains. So because Ice's mass is less than water, that's why it's able to float. In other words,we say ice is less dense than water
A volume of ice has less mass than the same volume of water. Hence, ice floats in water. Option (C) is correct.
What is density?The density of a material indicates the density of that material in a specific area. The density of a material is defined as its mass per unit volume. Density is a measurement of how closely matter is packed together. It is a distinct physical property of a specific object.
Archimedes, a Greek scientist, discovered the density principle. If you know the formula and understand the units, calculating density is simple. Density is represented by the symbol ρ, which can also be represented by the letter D.
Now, ice has less density compare to water. So, a certain volume of ice has less mass than the same volume of water. Hence, option(C) is correct.
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Barbara plotted an elevation below sea level on a number line and labeled it A. She plotted Point B above 0, a distance that is exactly as far from 0 as Point A is. Explain what you know about Point B.
Answer:
Point A is the same distance below 0 as Point B is above 0.
Point B is a positive integer.
Since a number and its opposite are the same distance from 0 in opposite directions, Point B is the opposite of Point A.
Explanation:
Answer:
Sample Response: Because Point A is negative and the same distance below 0 on the number line as Point B is above it, Point B is both positive and the opposite of Point A.
Explanation:
HELPPPPP
Jermaine runs exactly 2 laps around a 400 meter track.
Find displacement.
Answer:
0
Explanation:
she runs 2 whole laps around a 400 meter track, but she is always ending up back where she started, therefor there is no displacement.
List 2 examples of physical properties that don't
change if the sample size changes.
Answer:
Temperature, density
Explanation:
Physical properties of a substance are those properties that do not change the chemical composition of the substance. There are two types of physical properties namely: intensive property and extensive property.
Intensive properties are those physical properties that does not depend on the sample size of the substance involved. Examples of intensive physical properties are temperature, density, boiling point. For example, the size or amount of a substance does not determine the the TEMPERATURE or BOILING POINT of the substance.
HEY CAN ANYONE PLS ANSWER DIS!!!!!!!
Answer:
A) the one with the lower boiling point.
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Elements in the same______
are more chemically similar.
THIS IS URGENT!!!!
Answer:
group
Explanation:
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the energy lost between trophic levels why?
Answer:
Explanation:
Energy decreases as it moves up trophic levels because energy is lost as metabolic heat when the organisms from one trophic level are consumed by organisms from the next level. Trophic level transfer efficiency (TLTE) measures the amount of energy that is transferred between trophic levels
The law of conservation of energy tells us
A. that energy can be transformed from one form to another
B. energy cannot be created or destroyed
C. the total amount of energy will remain the same
D. All of the above
Answer:
it is A
Explanation:
because energy can neither be created nor destroyed - only converted from one form of energy to another.
How far will a car travel in 2 hours at 20 km/hr?
20 km
40 km
80 km
O km
Answer:
It should be 40
Answer:
I think it is 40km sorry if my Answer is wrong
a nucleus with four protons have a total positive charge of what
Answer:
The name of element is Beryllium.
Explanation:
Given that,
A nucleus with four protons have a total positive charge.
Suppose, what is the name of element ?
We know that,
The name of element which have 4 positive charge is Beryllium.
Beryllium is a element which is symbol is Be.
Atomic number of beryllium is 4 and atomic mass is 9.
The number of neutrons are 5.
Hence, The name of element is Beryllium.