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
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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a leaky faucet is dripping at a rate of 1 pint per hour how many hours to fill 10 gallons
Answer:
80 hours :)))))))))))))
Which of the following choices is not part of the scientific method
Answer:
What are the choices?
Explanation:
Emmy kicks a soccer ball up at an angle of 45° over a level field. She watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. Assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. Consider only the time that the ball is in the air, after being kicked but before landing. Take "north" and "up" as the positive x ‑ and y ‑directions, respectively, and use g≈10 m/s2 for the downward acceleration due to gravity.
Answer:
v_y = 10 - 10t
v_x = 10 m/s
Explanation:
This is a projectile launch where the x axis and y axis will be treated independently.
Now, towards the north on the x-axis, there will be no acceleration and so the speed is constant
So, vₓ = v₀ₓ
Whereas, on the vertical y - axis, the acceleration due to gravity with be negative since it's in a downward direction.
Thus, the equation is;
v_y = v_oy - gt
Now, the initial velocity component will be;
cos 45 = v₀ₓ/v₀
And sin 45 = v_₀y/v₀
Thus, we have;
v₀ₓ = v₀(cos 45)
Also, v_oy = v₀(sin 45)
Now, the initial velocity would be gotten from the equation of range which is;
R = (v₀² × sin 2θ)/g
Making v₀ the subject, we have;
v₀ = √(Rg/sin 2θ)
We are given;
R = 20 m
g = 10 m/s²
θ = 45°
Thus;
v₀ = √[20 × 10/(sin (2 × 45))]
v₀ = √200
v₀ = 14.14 m/s
Thus;
v₀ₓ = 14.14(cos 45) = 10 m/s
v_oy = 14.14(sin 45) = 10 m/s
Earlier we saw that;
v_y = v_oy - gt
Thus;
v_y = 10 - 10t
Also,we saw that;
vₓ = v₀ₓ
Thus;
v_x = 10 m/s
For the graph, we will use times of t = 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2
Thus, for each of those values of t, we will have the following values of v_oy
t (s) v_oy (m / s)
0 10
0.2 8
0.4 6
0.6 4
0.8 2
1.0 0
1.2 -2
Graph is attached
What is the formula for speed?
गतत का सूत्र क्या है?
A : Distance covered/Time | तय की गई
दरूी/समय
B : Change in velocity/Time | वेग में
पररवतषन/समय
C : Distance in definite direction /Time |
तनजचचत टदशा में दरूी/समय
D : Change in momentum/Time | संवेग में
पररवतषन/समय
Ans:
A : Distance covered/Time | तय की गई
दरूी/समय
Explanation:
Formula for speed = Distance covered/Time
Therefore,
Option A is correct.
Answer:
a.distance÷timetaken
Explanation:
The formula for speed is speed = distance ÷ time. To work out what the units are for speed, you need to know the units for distance and time. In this example, distance is in metres (m) and time is in seconds (s), so the units will be in metres per second (m/s).
2
A crane has an arm to which is attached a frictionless pulley. A cable passes over the pulley and
supports a load of 10 kN as shown.
frictionless pulley
104N
30
30°
crane arm
load
10 KN
The crane arm exerts a force F on the pulley.
What is the value of F?
C
8.7 KN
10 KN
D
A
17 kN
B
5.0 KN
Answer:
17kN
Explanation:
The force of 10 kN in the cable and the load of 10 kN both have a component along the crane arm.
The force F exerted by the crane arm on the pulley is the sum of these 2 components.
Component of force in cable along the crane arm = 10 cos 30°
Component of load along the crane arm = 10 cos 30°
Considering the forces on the pulley,
F = 10 cos 30° + 10 cos 30°
Force F = 17.32 kN = 17 kN
1) A rigid tank contains 2 kg of 134a refrigerant at 800 kPa and 120°C. Determine tank volume and total internal energy.
Answer:
V = 0.07525 [m³]
U = 655.74 [kJ]
Explanation:
To solve this problem we must use the superheated refrigerant table for refrigerant 134a. The attached image shows the specific volume and specific internal energy values for a pressure of 800 [kPa] and a temperature of 120 [°C].
m = mass =2 [kg]
the specific volume = v = 0.037625 [m³/kg]
The volume of the tank can be found using the following expression:
V = v*m
V = 0.037625*2 = 0.07525 [m³]
The Specific internal energy = u = 327.87 [kJ/kg]
U = u*m
U = 327.87*2 = 655.74 [kJ]
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Tom, a 13 year old boy, wants to train for a 5k Fun Run that his school is organizing. What area of fitness should Tom focus on? What activities should he do to improve this area?
Answer:
cardiovascular endurance
Explanation:
In order for Tom to successfully complete the marathon, he should focus on being able to maintain a constant pace without tiring easily.
the graph below represents the relationship between velocity and time for an object moving along a straight line.
What is the magnitude of the object's acceleration?
1. 5.0 m/s^2
2. 8.0 m/s^2
3. 10. m/s^2
4. 20. m/s^2
Answer:
10. m/s^2
Explanation:
40-(-10)= 50
50/5 =10
This question can simply be answered by using the slope of the velocity-time graph.
The correct answer for the magnitude of the acceleration is "3. 10 m/s²".
Since the graph between the velocity and the time is in the form of a straight line. Hence, the acceleration can be calculated as the slope of this line. We will use the first and last point of the line to calculate the slope (acceleration):
[tex]Acceleration = Slope = \frac{v_2 - v_1}{t_2-t_1}[/tex]
where,
v₁ = initial velocity from the graph = - 10 m/s
v₂ = final velocity from the graph = 40 m/s
t₁ = initial time from the graph = 0 s
t₂ = final time from the graph = 5 s
Therefore,
[tex]Acceleration = \frac{40\ m/s\ -\ (-\ 10\ m/s)}{5\ s\ -\ 0\ s}[/tex]
Acceleration = 10 m/s²
The attached picture shows the types of a velocity-time graph.
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Which statement describes S waves? A. They move side to side.B.They arrive betore P waves. C. They travel through liquids D. They occur at Earth's surtace.
Answer: they move side to side
Explanation:
i took the test
Add the following vectors:
(a) (12, 5) + (6, 3)
(b) (−3, 8) + (6, −2)
(c) (3, 8, −7) + (7, 2, 17)
(d) (a, b, c) + (d, e, f)
Answer:
a. (18,8)
b. (3, 6)
c. (10, 10, 10)
d. (a+d, b+e, c+f)
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Atoms tend to be stable and nonreactive if they have six valence electrons.
Select one:
O True
O False
Answer:
True
Explanation:
Why is it important to warm up your muscles?
Warming up the muscles increases lactic acid build up
Warming up the muscles increases temperature and flexibility of your muscles Warming up the muscles increases your risk of injury
All of the above
A ball is thrown upward in the air with an initial velocity of 40 m/s. How long does it take to
reach back to the point it was thrown from?
Answer:
You need the definition of acceleration (a=Vf-Vi/t) and 1 equation of linear motion (deltaX = Vi×t + 1/2×a×t^2). Since you know a is constant (gravity) and you know your initial Vi to be 40 m/s and your final velocity Vf to be zero (maximum height), then you can use thhe definition of acceleration to find time.
-9.81m/s^2 = (0-40m/s)/t
t = (-40)/(-9.81) s
t = 4.077s
Now that you have time, you should know all but deltaX in the equation of linear motion.
dX = (40m/s)(4.077s) + (1/2)(-9.81m/s^2)(4.077s)^2
dX = (163.099m) — (81.549m)
dX = 81.55m
what are Newton's 3 laws
Answer:
Newton 3 laws
Explanation:
1.object will not change its motion unless a force acts on it . 2.the force on an object is equal to it's time mass on acceleration. 3. When 2 o jecys interact they apply forces to each other of equal.
A rubber cord catapult has cross-sectional area
25mmand initial length of rubber cord is 10c.
Its is stretched to 5cm and then released to
project a missile of mass 5gm. Taking
Yubber = 5x108N/m² velocity of projected
missile is :
(1) 20ms -
(2) 100ms
(3) 250ms
(4) 200ms)
A 10 [kg] object is dropped from rest. a. How far will it drop in 2 [s]?
Answer:
y=0.5 g t^2
=0.5*10*2^2
=20 m
Can you help me please! Love you
Answer:
I think its B. wait...U love ME?????
a hole is punched at a height h in the side of a container of height h0. The container is full of water. If the water is to shoot as far as possible horizontally, (a) how far from the bottom of the container should the hole be punched? (b) Neglecting frictional losses, how far (initially) from the side of the container will the water land?
What is called mass per unit
volume of a substances? | ककसी पदाथष के
द्रव्यमान प्रतत इकाई आयतन को क्या कहते हैं?
A : Mass | द्रव्यमान
B : Weight | भार
C : Density | घनत्व
D : Volume | आयतन
Ans:
C : Density | घनत्व
Answer:
Density
Explanation:
The definition of density of a substance is the quotient between its mass and its volume. Such results in the mass per unit of volume.
which produces wave particles that move and displace one another
Answer:
a guitar?
Explanation:
A bus rolls to a stop along a horizontal road without the driver applying the brakes,
What answer choice BEST explains why this occurred?
A. The natural state of the bus is not to be in motion.
B. The bus ran out of momentum.
C. The force of gravity slowed the bus until it stopped.
D. The opposing force of friction stopped the train.
Answer:
should be d because friction allows things to go faster or slower
Erica is working in the lab. She wants to remove the fine dust particles suspended in a sample of oil. Which method is she most likely to u
Answer: Option A is your answer
Explanation:
Describe two similarities and two differences between electric and magnetic field lines. (Consider such things as where they originate and terminate, how they are related to the direction and strength of the field, whether they are closed curves or lines, and whether there's anything you can say about their flux through a closed surface.). Others
Answer:
Please see below as the answer is self- explanatory.
Explanation:
Similarities:The field vector is tangent to the field lines at any point of the trajectory.The density of field lines is proportional to the strength of the field.Differences:Electrostatic Field lines originate in charge distributions of positive charges and end in charge distributions of negative charges.Magnetic Field lines are closed lines, due to there are no isolated magnetic charges discovered yet.Electrostatic Field lines have the direction of the trajectory taken by a positive test charge.Magnetic Field lines have the direction defined by right-hand rule.Vector net flux of electrostatic field lines through a closed surface is equal to the net charge enclosed by the surface.Vector net flux of magnetic field lines through a closed surface is always zero.Similarities
Field vectorDensity of field linesDifferences
Dispersions of positive charges .No separated attractive charges.Electric and Magnetic field lines.Similarities:
The field vector is tangent to the field lines at any point of the trajectory. The density of field lines is relative to the quality of the field.
Differences:
Electrostatic Field lines begin in charge dispersions of positive charges and conclusion in charge dispersions of negative charges.
Magnetic Field lines are closed lines, due to there are no separated attractive charges found yet.
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Select the correct answer.
Which scientist discovered the relationship between electricity and magnetism?
OA.
Nikola Tesla
OB
Alessandro Volta
OC.
Hans Christian Oersted
OD
Isaac Newton
Answer:
Hans Christian Oersted
Explanation:
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Explain why your weight would change if you went to the moon, but your mass wouldn’t.
The moon's gravitation force is determined by the mass and the size of the moon. Since the moon has significantly less mass than the Earth, it will not pull objects toward itself at the strength that Earth will.
A projectile is fired into the air at an angle of 50° above ground level and hits a target downrange. Neglecting air drag, it will also hit the target if fired at the same speed at an angle of
Answer:
18 m/s
Explanation:
Range of a projectile on level ground is:
R = v₀² sin(2θ) / g
14.3 m = v₀² sin(2×13°) / 9.8 m/s²
v₀ = 17.9 m/s
Rounded to two significant figures, the launch speed was 18 m/s.
If the bullet is launched at an angle of 50 degrees above ground level, the target will be struck. The angle remains the same. The launch angle obtained is 50 degrees.
Given:
The initial shot was fired at an angle of 50 degrees above ground.
The projectile's starting velocity (v) and magnitude of velocity will remain constant if it is shot at the same pace.
Let the angle of the projectile is x,
The horizontal component of velocity can be calculated as follows:
[tex]v(x) = v * cos(x)[/tex]
We can write:
since the horizontal part of velocity remains constant:
[tex]v(x1) = v(x2)[/tex]
[tex]cos(50) = cos(x)[/tex]
[tex]50 = x[/tex]
Therefore, if the projectile is launched at the same speed at a 50° angle above ground level, it will strike the target.
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The correct response is given when the angle is asked a question.
PLEASE PLEASE HELP PICTURE INCLUDED
Answer:
a is the answer
Explanation:
which graph best demonstrates the general relationship between mass and temperature similar to the trend of thermal energy absorbed by your sand and water samples
Answer: the first one
Explanation: got it right on edg
Answer:
The first graph
Explanation:
Correct on Edge 2022! :]