Answer:
The final velocity v₂ is 45 m/s
The highest point reached by the rocket is 101.25 m
The total time spent in air by the rocket is 7.5 s
Explanation:
Given;
initial velocity of the rocket, v₁ = 0
final velocity of the rocket, v₂ = ?
upward acceleration of the rocket, a = 15 m/s²
time of acceleration, t = 3 s
The final velocity is given by;
v₂ = v₁ + at
v₂ = 0 + (15 x 3)
v₂ = 45 m/s
The highest point reached by the rocket is given by;
v² = u² + 2ah
where;
u is the initial velocity of rocket when it started decelerating.
thus, u = v₂
v is the final velocity of the rocket at its highest point = 0
0 = v₂² + 2ah
0 = (45)² + (2 x -10 )h
0 = 2025 - 20h
20h = 2025
h = 2025 / 20
h = 101.25 m
Time taken for the rocket to reach its highest point is given by;
h = ut + ¹/₂at²
101.25 = 45t + ¹/₂(-10)t²
101.25 = 45t - 5t²
5t² - 45t + 101.25 = 0
t² - 9t + 20.25 = 0
t = 4.5 s
The total time spent in air by the rocket is given by;
T = upward time + downward time
T = 3 s + 4.5 s
T = 7.5 s
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:
why would it motivate Hollywood to use more realism in special effects?
Answer:
Explanation:
the search for authenticity in films, motivated Hollywood to use more realism in special effects.
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.
If an object is thrown down with force from the top of a building, at a speed of 20.0 m/s, and it hits the ground with
a speed of 40.0 m/s.
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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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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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
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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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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the energy transferred by a force of a moving object
Answer:
kinetic or mechanical cant remember
Explanation:
Answer:
Hey!!
Kinetic Energy is your answer!
Explanation:
I hope this helped you!
can someone please help me answer this in the next 15 minutes. ill give a brainiest to whoever can help me. tysm if u do!! :))
Answer: a
Explanation:
Answer: it is a
Explanation: the graph represents the number of speed running and the amount of you add 4 +—0.4 is -0.8! Byee! Plz give me brainliest! Ty! Have a good day!!
An Alaskan rescue plane traveling 46 m/s drops a package of emergency rations from a height of 101 m to a stranded party of explorers. The acceleration of gravity is 9.8 m/s^2. Where does the package strike the ground relative to the point directly below where it was released? Answer in units of m.
Answer:
The package strikes 207 m at the ground relative to the point.
Explanation:
Given that,
Speed = 46 m/s
Height = 101 m
Acceleration = 9.8 m/s²
We need to calculate the time
Using equation of motion
[tex]s=ut+\dfrac{1}{2}gt^2[/tex]
Put the value in the equation
[tex]101=0+\dfrac{1}{2}\times9.8\times t^2[/tex]
[tex]t=\sqrt{\dfrac{2\times101}{9.8}}[/tex]
[tex]t=4.5\ sec[/tex]
We need to calculate the distance where the package strikes
Using formula of distance
[tex]x=vt[/tex]
Put the value into the formula
[tex]x=46\times4.5[/tex]
[tex]x=207\ m[/tex]
Hence, The package strikes 207 m at the ground relative to the point.
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
Water is formed when two hydrogen atoms bond to an oxygen atom. The hydrogen and the oxygen in this example are different
They both are two different elements.SO the answer is Element
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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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.
When walking barefoot, Kevin can walk across the grass easily, but when he crosses the paved street, the street is hot and burns his feet. At the beach he walks quickly across the hot sand to the cool water. Why do some substances feel hot to his feet and others do not? Radiation is heat transfer through waves. Specific heat is the amount of energy required to raise the temperature of a substance 1 degree C.
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.
please help! newton's laws. please give a legit answer
Answer:
yuhhh
Explanation:
get into it
You are in a car moving at 50 mph to the right, from the reference frame of the ground. A truck is next to you moving at 30 mph to the right, also from the reference frame of the ground. Which is true from your reference frame of the car?
a. The truck would appear to stand still.This answer is incorrect.
b. The truck would appear to be moving forward.
c. The truck would appear to be moving backward.
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
How much heat is released by 38 gram sample of water to freeze
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:
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.
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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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
please mark me as brainliest
Rock X is released from rest at the top of a cliff is on earth. A short time later, Rock y is released from rest from the same point as rock X. Both rocks fall for several seconds before landing on the ground directly below the cliff. Frictional forces are considered to be negligible. Which of the following graph correctly shows the vertical velocity of rock X as a function of time? Take the positive direction to the upward.
Answer:
The graph that correctly shows the vertical velocity is B. since the velocity is negative and increases linearly over time
Explanation:
When an object is dropped from rest its movement is ruled only by the effect of gravity.
The acceleration of gravity [tex]g=9.8\ m/s^2[/tex] makes the object gain speed with a linear relation as shown:
vf = g.t
If we take the positive direction to be upward, then the speed will always be negative since the object will go against the positive direction.
Thus, the graph that correctly shows the vertical velocity is B. since the velocity is negative and increases linearly over time
From the given graphs, only the second graph (option B) started from rest (0) and later increased with time.
The given parameters;
Rock XRock yinitial velocity of Rock X = 0The final vertical velocity of the rock X after a short time "t" is calculated as follows;
[tex]v_y_f = v_y_i + gt\\\\v_y_f = 0 + 9.8t[/tex]
The vertical velocity of the rock x will increase with time as it moves downwards.
Therefore, we can conclude that, from the given graphs, only the second graph (option B) started from rest (0) and later increased with time.
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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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In the heart, what separates the oxygenated and deoxygenated blood?
A. Ventricle
B. Vessel
C.septum
D.atrium
Answer:
C. septum
Explanation:
The septum is the partition separating the right ventricle from the left ventricle. The right ventricle pumps deoxygenated blood to the lungs, and the left ventricle pumps oxygenated blood to the rest of the body.
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]