Complete Question
A sled of mass m is coasting at a constant velocity on the ice covered surface of a lake. Three birds, with a combined mass 0.5m, gently land at the same time on the sled. The sled and birds continue sliding along the original direction of motion. How does the kinetic energy of the sled and birds compare with the initial kinetic energy of the sled before the birds landed?
a) The final kinetic energy is one half of the initial kinetic energy.
b) The final kinetic energy is one third of the initial kinetic energy.
c) The final kinetic energy is one quarter of the initial kinetic energy.
d) The final kinetic energy is one ninth of the initial kinetic energy.
e) The final kinetic energy is equal to the initial kinetic energy
Answer:
The correct option is b
Explanation:
From the question we are told that
The mass of the sled is m
The mass of the three birds is [tex]m_b = 0.5 m[/tex]
Generally from the law of momentum conservation,
The initial momentum of the boat = final momentum of the boat
Hence
[tex]m * v = (m_b+ m) * v_2[/tex]
=> [tex]m v = (0.5m+ m) * v_2[/tex]
=> [tex]m v = 1.5m* v_2[/tex]
Here v is the velocity of the boat before the birds landed and [tex]v_2[/tex] is the velocity after the birds landed
So
[tex]v_2 = \frac{2}{3} v[/tex]
Generally the initial velocity of the boat before the birds landed is mathematically represented as
[tex]K_i = \frac{1}{2} * m * v ^2[/tex]
Generally the final velocity of the boat when the birds have landed is mathematically represented as
[tex]K_f = \frac{1}{2} * (m_b + m ) * v_2^2[/tex]
=> [tex]K_f = \frac{1}{2} * (0.5m + m ) * (\frac{2}{3} v)^2[/tex]
=> [tex]K_f = \frac{1}{2} * 1.5m * (\frac{2}{3} v)^2[/tex]
=> [tex]K_f = \frac{1}{2} * 1.5m * \frac{4}{9} v^2[/tex]
=> [tex]K_f = \frac{1}{2}m v^2 * \frac{1}{3}[/tex]
Comparing this equation with that of the initial kinetic energy
=> [tex]K_f = \frac{1}{3} K_i[/tex]
The kinetic energy of the sled and birds is one-third the initial kinetic energy of the sled before the birds landed.
What is kinetic energy?When an object is in motion, then the energy possessed by the object at the state of motion is known as its kinetic energy.
Given data -
The combined mass of three birds is, M = 0.5m.
Let m be the mass of the sled. Then applying the conservation of linear momentum as,
The initial momentum of the boat = final momentum of the boat
mv = (M + m)v'
v is the velocity of the boat before the birds landed and v' is the velocity after the birds landed.
mv = (0.5m + m)v'
mv = 1.5mv'
v = 3/2 v'
or
v' =2/3v
The initial kinetic energy of the boat before the birds landed is mathematically represented as
[tex]K_{1}= \dfrac{1}{2}mv^{2}[/tex]
And the final kinetic energy of the boat when the birds have landed is mathematically represented as,
[tex]K_{2}=\dfrac{1}{2}(M+m)v'^{2}\\\\K_{2}=\dfrac{1}{2}(1.5m) \times 4/9v^{2}\\\\K_{2}=\dfrac{1}{3} \times \dfrac{1}{2}mv^{2}\\\\K_{2}=\dfrac{1}{3} \times K_{1}[/tex]
Thus, we can conclude that the kinetic energy of the sled and birds is one-third the initial kinetic energy of the sled before the birds landed.
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7. A 2kg block is acted on by two forces F1 and F2 as shown in the diagram. If the magnitude of F1 = 13N and F2 = 11N. If the coefficient of kinetic friction is .23, find (A) The normal force exerted on it by the floor. (2 pts) (B) The acceleration on of the block (2 pts)
Answer:
A.) 17.04 N
B.) 10.76 m/s^2
Explanation:
Given that a 2kg block is acted on by two forces F1 and F2 as shown in the diagram. If the magnitude of F1 = 13N and F2 = 11N. If the coefficient of kinetic friction is .23,
A.) To find the normal force exerted on it by the floor, we need to first calculate the vertical forces of the ropes.
The vertical force on F1 = 13 sin 30
F1 = -6.5 N
The vertical force on F2 = 11 sin 21
F2 = 3.94
The resultant force = - 6.5 + 3.94
Resultant force = - 2.56
The normal force = mg - 2.56
The normal force = 2 × 9.8 - 2.56
The normal force = 19.6 - 2.56
The normal force = 17.04 N
(B) The acceleration on of the block will be achieved by first calculating the horizontal force.
For F1 = 13Cos 30
F1 = 11.26N
For F2 = 11 cos 21
F2 = 10.27
the resultant force = 11.26 + 10.27
Horizontal force = 21.53N
Force = mass × acceleration
21.53 = 2 × a
a = 21.53 / 2
Acceleration a = 10.76 m/s^2
What President is responsible for eliminating most vending machines from the cafeterias of public schools ?
Answer:president obama
Explanation:Why this is because he took a of mayor Bloomebergs amti obeity book and made new rules for snack foods.
A yo-yo is attached to the end of a string. A professional yo yo is spinning it by the string around in a circular
motion. All of a sudden he lets go of the string. What direction is the yo yo moving in initially?
Answer:
counter-clockwise
Explanation:
An Astronaut on the Moon drops a rock straight downward from a height of 1.25 meters. If the acceleration of gravity on the Moon is 1.62 meters per second squared, what is the speed of the rock just before it lands?
Answer:
Since the astronaut drops the rock, the initial velocity of the rock is 0 m/s
We are given:
initial velocity (u) = 0 m/s
final velocity (v) = v m/s
acceleration (a) = 1.62 m/s/s
height (h) = 1.25 m
Solving for v:
From the third equation of motion:
v²-u² = 2ah
replacing the variables
v² - (0)² =2 (1.62)(1.25)
v² = 1.62 * 2.5
v² = 4 (approx)
v = √4
v = 2 m/s
The speed of the rock just before it lands is 2 m/s
PLZ HELP!!!!!!! ILL GIVE U BRAINLIEST
Answer:
Claim: Heart Rate for Sarah and Matt (this would be the homeostasis AT REST and throughout the graph time)
Evidence: The Graph and the HR/S and its evidence towards the heart rate/beats every 15 seconds, due to the homeostasis being a specific time limit and due to the specific heart rate of Matt and Sarah ONLY.
Explanation: A/B Checkpoint throughout the homeostasis (this would be heart rate/trial throughout the time of the graph)
Conclusion: Matt was further away ONLY BECAUSE Sarah has a higher Heart Rate during the time on the graph, which can represent how long they did something to increase/decrease from and where the homeostasis would be located.
Answer:
Claim: Heart Rate for Sarah and Matt (this would be the homeostasis AT REST and throughout the graph time)
Evidence: The Graph and the HR/S and its evidence towards the heart rate/beats every 15 seconds, due to the homeostasis being a specific time limit and due to the specific heart rate of Matt and Sarah ONLY.
Explanation: A/B Checkpoint throughout the homeostasis (this would be heart rate/trial throughout the time of the graph)
Conclusion: Matt was further away ONLY BECAUSE Sarah has a higher Heart Rate during the time on the graph, which can represent how long they did something to increase/decrease from and where the homeostasis would be located.
Two wires A and B made of the same material and having the same lengths are connected across the same voltage source. If the power supplied to wire A is six times the power supplied to wire B, what is the ratio of their diameters
Answer:
sqrt (3) : sqrt (2)
Explanation:
Given that Two wires A and B made of the same material and having the same lengths are connected across the same voltage source.
Since they are both made of the same material, they will have the same resistivity.
Resistance is directly proportional to the length of the wire and inversely proportional to the cross sectional area.
Resistance R =1/ πr^2
If the power supplied to wire A is six times the power supplied to wire B, that is,
Pa = 6Pb
Where
Power P = IV
Since the same voltage passes through both wires,
P = V^2/R
Substitutes resistance R into the equation .Therefore,
V^2 ÷ 1 / πr^2 = 6( V^2 ÷ 1 / πr^2 )
V will cancel out , leaving
πr^2 = 6πr^2
Pi( π) will also cancel out. And since diameter d = 2r
r = d/2
Substitutes r into the equation
(d/2)^2 = 6( d/2)^2
d^2/4 = 6( d^2/4)
d^2/4 = 3d^2/2
da^2/2 = 3db^2
(Da/Db)^2 = 3/2
Da : Db = sqrt (3) : sqrt (2)
therefore, the ratio of their diameters is
sqrt (3) : sqrt (2)
The ratio of the diameter of Wire A to Wire B is; √6 : 1
What is the power in the wire?Since both wires are made of the same material, they will definitely have the same resistivity.
Formula for the resistance with area is;
R = 1/A = 1/(πr²)
We are told that the power supplied to wire A is six times the power supplied to wire B. Thus;,
Pa = 6Pb
Since the same voltage passes through both wires, then formula for power in both cases is; P = V²/R. Thus;
V² ÷ (1/πr_a²) = 6(V² ÷ (1/πr_b²))
V and π will cancel out to give;
r_a² = 6r_b²
We know that radius; r = d/2
Thus;
(d_a/2)²= 6(d_b/2)²
d_a²/4 = 6(d_b²/4)
(d_a/d_b)² = 6
d_a/d_b = √6 : 1
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1)
You travel east at 50 km/hr and then north at 75 km/hr. What is your Resultant Velocity in km/h?
(Remember the angle) (5pts)
Answer:
15
Explanation:
Which best describes a difference between laser light and regular light?
Laser light is less concentrated.
Laser light has a beam that spreads out.
O Laser light is made of one specific color.
O Laser light pumps out light particles one at a time.
Answer: the correct answer should be B
Explanation:
The statement that, best describes a difference between laser light and regular light is laser light is made of one specific color.
What is laser light?A laser light is a light produced by a laser
Laser itself, is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.
Difference between laser light and regular lightRegular light is non-directional and inconsistent, while laser light shows directional and highly consistent distribution.Regular light is a mixture of electromagnetic waves of different wavelengths while Laser light is monochrome (one colour).Thus, the statement that, best describes a difference between laser light and regular light is laser light is made of one specific color.
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The Plateau of Tibet is a dry place. Do you think the wide-leafed plant fossils found on the plateau could grow there today? Explain your answer.
No, I dont think that they could grow there now in this day and age becuase the Plateu of Tbiet is very dry and also a little bit dusty. They barely even have grass down there. Wide leaf plants susually grow somewhee like the rainforest where it is warm, sunny, and rainy but in a place like Tibet, I don't think that they would be able to survive there.
Answer:
No. The leaves are similar to those of plants found in lower elevations with plenty of rainfall, like the plants seen at the lower elevations of the Himalayas. Because the Plateau of Tibet has risen over time, it is not likely that these plants could live in these colder climates.
Explanation:
Sample answer from pluto
A coin is rolling across a table at 0.23 m/s. It rolls off the table and lands 0.15 meters away from the edge of the table. How high is the table? Show all your work.
Answer:
The table is 2.08 m high
Explanation:
Horizontal Motion
When an object is thrown horizontally with a speed vo from a height h, the range or maximum horizontal distance traveled by the object can be calculated as follows:
[tex]\displaystyle d=v\cdot\sqrt{\frac {2h}{g}}[/tex]
If we know the range d = 0.15 m and the speed v = 0.23 m/s, we can solve the above equation for h:
[tex]\displaystyle h=\frac{d^2\cdot g}{2v^2}[/tex]
[tex]\displaystyle h=\frac{0.15^2\cdot 9.8}{2\cdot 0.23^2}[/tex]
[tex]\boxed{h=2.08\ m}[/tex]
The table is 2.08 m high
Which shows the correct steps in the formation of an ionic bond between these atoms?
A magnesium atom accepts six electrons from the fluorine atoms → Each fluorine atom donates three of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom accepts two electrons from the fluorine atoms → Each fluorine atom donates one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion → Each fluorine atom becomes a -1 ion
Answer:
D) A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion → Each fluorine atom becomes a -1 ion
Explanation:
sorry if its a bit late
The correct steps in the formation of an ionic bond are A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion. The correct option is D.
What are ionic bonds?The electrical attraction between two ions with opposing charges creates an ionic bond, also known as an electrovalent bond, in a chemical molecule.
Ionic compounds are created by ionic bonds, while covalent bonds create covalent compounds. Ionic bonds are created by a complete transfer of electrons, whereas covalent bonds are created by sharing electrons.
Covalent bonds are weaker than ionic ones. Ionic compounds have higher melting and boiling points.
Therefore, the correct option is D.
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50 POINTS PLSS
Your car is initially at rest when your hit that gas and the car begins to accelerate at a rate of 2.857 m/s/s. The acceleration lasts for 15.5 s. What is the final speed of the car and how much ground does it cover during this acceleration?
Answer:I think the answer is 5.43 I don’t rlly know
Explanation:
Which of the following is not a part of the appendicular skeleton
a. femur
b. scapula
c.phalanges
d.hyoid
Answer:
Hyoid
Explanation:
The hyoid is located in the neck area, not the limbs.
What is velocity in science
Answer:
Velocity is the rate at which the position changes. The average velocity is the displacement or position change (a vector quantity) per time ratio.
Hope this helps! ^-^
Answer:
Velocity is the speed at which something moves in one direction.
Explanation:
Hope this helps : )!!
The most interpersonal constructive passion response to relational conflict is..
Answer:
loyalty
Explanation:
show answer No Attempt 50% Part (b) Calculate the non-relativistic speed of these electrons v in m/s.
Complete Question
The complete question is shown on the first uploaded image
Answer:
The value is [tex]v = 9.18 *10^{6} \ m/s[/tex]
Explanation:
From question we are told that
The potential difference is [tex]\Delta V = 0.24 kV = 0.24 *10^{3} \ V[/tex]
Generally the the non-relativistic speed of these electrons is mathematically represented as
[tex]v = \sqrt{\frac{2 * e * \Delta V}{m} }[/tex]
Here m is the mass of an electron with value [tex]m = 9.11 *10^{-31 } \ kg[/tex]
e is the charge on an electron with value [tex]e = 1.60 *10^{-19} \ C[/tex]
So
[tex]v = \sqrt{\frac{2 * 1.60 *10^{-19} * 0.24 *10^{3} }{9.11*10^{-31}} }[/tex]
=> [tex]v = 9.18 *10^{6} \ m/s[/tex]
Your are part of a team to help design the atrium of a new building.Your boss, the manager of the project, wants to suspend a 6.2 kg sculpture high over the room by hanging it from the ceiling using thin, clear fishing line (string) so that it will be difficult to see how the sculpture is held up. The only place to fasten the fishing line is to a wooden beam which runs around the edge of the room at the ceiling.The fishing line that she wants to use will hold 10 kg so she suggests attaching two lines to the sculpture to be safe. Each line would come from the opposite side of the ceiling to attach to the hanging sculpture. Her initial design has the first line making an angle of 12.67∘with the ceiling and the second line making an angle of 16.15∘ with the ceiling. She knows you took physics, so she asks you if her design can work.
How much force would the first line exert on the beam holding it up?
Assume that g=9.8 m/s−2.
Answer:
The answer is below
Explanation:
Given that the mass of the sculpture (m) = 6.2 kg, [tex]\theta_1=12.67^o,\theta_2=16.15^o[/tex]
[tex]Sum\ of\ horizontal\ force\ is\ zero\ hence:\\\\T_1cos(\theta_1)=T_2cos(\theta_2)\\\\T_1=\frac{T_2cos(\theta_2)}{cos(\theta_1)}\\ \\Sum\ of\ vertical\ force\ is\ zero:\\\\T_1sin(\theta_1)+T_2sin(\theta_2)=mg\\\\\frac{T_2cos(\theta_2)}{cos(\theta_1)}sin(\theta_1)+T_2sin(\theta_2)=mg\\\\T_2=\frac{mg}{\frac{cos(\theta_2)}{cos(\theta_1)}sin(\theta_1)+sin\theta_2} \\\\T_2=\frac{6.2*9.81}{\frac{cos(16.15)}{cos(12.67)}sin(12.67)+sin16.15} =123.1\ N\\\\[/tex]
[tex]T_1=\frac{T_2cos(\theta_2)}{cos(\theta_1)}=121.2\ N[/tex]
1.What is the mass of an object that weighs 98 N?
Answer:
10 kg
Explanation:
The path of a projectile fired at an angle above the horizontal is best described as
When the force applied to an object increases, the motion of the object
Answer:
Semen is the most important thing in the life cycle of life
What is the rate of acceleration of a hammer whose head goes from moving -2 m/s (downward) to +0.5 m/s (upward) when it hits and bounces off a hard rock ? The actual bounce takes 0.025 seconds
Answer:
[tex]a=100\ m/s^2[/tex]
Explanation:
Given that,
Initial velocity, u = -2 m/s
Final velocity, v = =.5 m/s
Time, t = 0.025 s
We need to find the rate of acceleration of a hammer. Acceleration is equal to the change in velocity divided by the time taken.
[tex]a=\dfrac{v-u}{t}\\\\a=\dfrac{0.5-(-2)}{0.025}\\\\a=100\ m/s^2[/tex]
So, the acceleration of the jet is [tex]100\ m/s^2[/tex].
WHat is the correct definnition for recovery heart rate ?
Answer:
when your heart rate is not high than normal or lower than normally
Explanation:
Recovery heart rate is when your heart recovers from a certain heart rate eg high heart rate or even low heart rate this means you heart is now functioning normally .
Answer:
Number of beats per minute the heart drops after exercise.
A stone is thrown vertically upward with the velocity of 25 m/s. How long day
it take to reach the maximum height? Also calculate the height
Answer:
The stone takes 2.55 sec to reach a maximum height of 31.89 m
Explanation:
Vertical Motion
When an object is thrown vertically up with a speed vo, it loses speed because of the effect of the gravity and gains height until the speed is eventually zero. The height attained at that time is called maximum height, and can be calculated as follows:
[tex]\displaystyle h_m=\frac{v_o^2}{2g}[/tex]
Since vo=25 m/s
[tex]\displaystyle h_m=\frac{25^2}{2\cdot 9.8}=31.89\ m[/tex]
Also, the time taken to reach the maximum height is calculated by:
[tex]\displaystyle t_m=\frac{v_o}{g}[/tex]
[tex]\displaystyle t_m=\frac{25}{9.8}=2.55\ s[/tex]
The stone takes 2.55 sec to reach a maximum height of 31.89 m
Suppose a rocket-propelled motorcycle is fi red from rest horizontally across a canyon 1.00 km wide. (a) What minimum constant acceleration in the x-direction must be provided by the engines so the cycle crosses safely if the opposite side is 0.750 km lower than the starting point? (b) At what speed does the motorcycle land if it maintains this constant horizontal component of acceleration? Neglect air drag, but remember that gravity is still acting in the negative y-direction.
Your car is initially at rest when your hit that gas and the car begins to accelerate at a rate of 2.857 m/s/s. The acceleration lasts for 15.5 s. What is the final speed of the car and how much ground does it cover during this acceleration?
Answer:
Vf = 44.56 [m/s]
Explanation:
In order to solve this problem we must use the following expression of kinematics.
[tex]v_{f} = v_{i}+(a*t)[/tex]
where:
Vf = final velocity [m/s]
Vi = initial velocity = 0
a = acceleration = 2.857 [m/s^2]
t = time = 15.5 [s]
Note: the initial velocity is equal to zero as the car begins its movement from rest, or with an initial velocity equal to zero.
Vf = 0 + (2.875*15.5)
Vf = 44.56 [m/s]
Sand is made of tiny pieces of rock that have been worn
down by wind and water. Explain why the formation of
sand is a physical change.
Answer:
Sand is a form of physical change because it shows how one object is being worn out (broken down) into another object by nature.
Explanation:
Can someone please help me
Answer:
grams= 4.8e-5
kilograms= 4.8e-8
centigrams= 0.0048
dekagrams= 4.8e-6
Explanation:
explain why a wrecking ball can destroy a building, but a yo-yo cant. Use the term kinetic energy in your explanation.
The kinetic energy of a body determines it's level of impact on the object in which it comes in contact with. Hence, the much larger kinetic energy exhibited by a wrecking ball compared to a yo-yo means that is has a much larger impact on a building than a yo-yo.
Kinetic Energy = 0.5mv²The kinetic energy of a body is a factor of it's velocity and mass as they are directly proportional.
The wrecking ball has a very large mass which is thousands of times larger than that of a yo-yo. Also, the velocity at which a wrecking ball is launched is higher than the velocity of a yo-yo.
This means that the kinetic energy of a wrecking ball is much higher than that of yo-yo. Hence, having much greater impact on a building compared to a yo-yo.
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Please help me with physics homework I just need help with C and D. Picture is included
Answer:
For C is B and for D is A
Explanation:
B because that's where the b car will do all the force to go up, and A because there the car doesn't have to do any force other than the natural, and it already brings that on it's own.
PLEASE HELP 50 POINTS!!!!!!!!!!!!!!!
Andrew and Deshawn are teammates on a high school soccer team. They’ve been playing soccer together for years. They both play the center forward position. Some years, Andrew is better than Deshawn and serves as the team’s starter. Other years, Deshawn is the stronger player and gets the most playing time. They are both very competitive with each other. Although they know each other well, they have never been friends.
In practice yesterday, the team was running drills in the rain. Deshawn slipped in the mud and collided with Andrew. Andrew hurt his knee badly in the fall and will have to sit out for several weeks.
The next day, Andrew told everyone at school that Deshawn hurt him on purpose to get more playing time. Deshawn retaliated by sharing private information about Andrew on social media. Andrew’s best friend Mateo saw the collision. He knows it was a complete accident.
Pick the role of Andrew, Deshawn, or Mateo.
What are the main issues/problems from this person’s perspective?
What ethical issues are involved for this person?
Why are these ethical issues relevant for this person?
How should the person you chose handle the situation?
Answer:
1. I pick the role of Mateo.
2. The main problems from Mateo's perspective are: He knows that the collision was a complete accident and that Deshawn did not injure Andrew on purpose. Because Andrew told everyone that Deshawn injured him on purpose, Deshawn did something unethical by sharing private information about Andrew on social media.
3. The ethical issues are: Andrew took his hurt and frustration of being injured and missing play time out on Deshawn, so he slandered him by saying that Deshawn hurt him on purpose. Deshawn then retaliated by sharing personal information about Andrew on social media, which is also unethical.
4. These issues are relevant to Mateo because he is Andrew's best friend AND he saw the incident happen and knows it was an accident.
5. If I was Mateo, I would talk to Andrew and explain to him that I know he is mad that he is injured and can't play for several weeks, but telling everyone that Deshawn did it on purpose wasn't right or good sportsmanship. I would encourage Andrew to meet with Deshawn with me and have Andrew apologize to Deshawn for saying it was his fault, and then encourage Andrew to go and tell everyone the real story. I would also encourage Deshawn to apologize for posting private information about Andrew, have Andrew ask him to take it down, and then ask Deshawn to post another post saying why he did it and that he was sorry. I would also encourage them to work together, since they are both star players.
Explanation: