2. a) A disc rotates about its axis at speed 25 revolutions per minute and takes 15 s to stop. Calculate the
i) angular acceleration of the disc.
ii) number of rotation of the dise makes before it stops.
The statement shows a case of rotational motion, in which the disc decelerates at constant rate.
i) The angular acceleration of the disc ([tex]\alpha[/tex]), in revolutions per square second, is found by the following kinematic formula:
[tex]\alpha = \frac{\omega_{f}-\omega_{o}}{t}[/tex] (1)
Where:
[tex]\omega_{o}[/tex] - Initial angular speed, in revolutions per second.[tex]\omega_{f}[/tex] - Final angular speed, in revolutions per second. [tex]t[/tex] - Time, in seconds.If we know that [tex]\omega_{o} = \frac{5}{12}\,\frac{rev}{s}[/tex], [tex]\omega_{f} = 0\,\frac{rev}{s}[/tex] y [tex]t = 15\,s[/tex], then the angular acceleration of the disc is:
[tex]\alpha = \frac{0\,\frac{rev}{s}-\frac{5}{12}\,\frac{rev}{s}}{15\,s}[/tex]
[tex]\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}[/tex]
The angular acceleration of the disc is [tex]\frac{1}{36}[/tex] radians per square second.
ii) The number of rotations that the disk makes before it stops ([tex]\Delta \theta[/tex]), in revolutions, is determined by the following formula:
[tex]\Delta \theta = \frac{\omega_{f}^{2}-\omega_{o}^{2}}{2\cdot \alpha}[/tex] (2)
If we know that [tex]\omega_{o} = \frac{5}{12}\,\frac{rev}{s}[/tex], [tex]\omega_{f} = 0\,\frac{rev}{s}[/tex] y [tex]\alpha = -\frac{1}{36}\,\frac{rev}{s^{2}}[/tex], then the number of rotations done by the disc is:
[tex]\Delta \theta = 3.125\,rev[/tex]
The disc makes 3.125 revolutions before it stops.
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The weather that characterizes an area is the O latitude of that area O barometric pressure of that area climate of that area O geography of that area
Answer:
climate of that area
Explanation:
A box is 30 cm wide, 40 cm long and 25 cm high. Calculate the volume of the box in cubic centimeter.
A) 3,000
B) 30,000
C) 15,000
D) 1,200
Answer:
The correct answer would be A: 3,000.
Explanation:
To find the volume of a box, you have to do l * w * h. You multiply 30, 40, and 25 which gives you an answer of 3,000 cubic centimeters.
what is one measurement needed to calculate the speed of an object
Answer:
The equation for speed is simple: distance divided by time. You take the distance traveled (for example 3 meters), and divide it by the time (three seconds) to get the speed (one meter per second).
Explanation:
i just need help plzzzz
Answer:
I think D it's the correct answer!! Let me know if i'm wrong
Explanation:
Bài 1. Một vật được đặt trên một mặt phẳng nghiêng hợp với mặt phẳng nằm ngang một góc = 300.
Answer:
3q
Explanation:
can anyone heelp me pls
Answer:
Lotion - Semisolid
Suspension - Liquid
Capsule - Solid
Describe what causes the planets to stay in orbit around the Sun
Answer:
Gravitional pull or gravity
Explanation:
Its that simple
Which can occur during a physical change? (SELECT ALL THAT APPLY!.)
The amount of energy within a substance can change.
The shape of a piece of matter can change.
The chemical reaction produces a new substance.
The atoms of the substance can permanently change.
Answer:
C, B, and D are ones i think i know that can occur during a physical change
Explanation:
what is the minimum mass in Mol. of plutonium 234 needed to reach a critical mass nuclear reaction?
Answer:
vddvdvvdvffdfvd
Explanation:
A particle of mass m is fired upwards from the surface of a planet of mass M
and radius R with velocity
Show that the maximum height the particle attains is R/3.
At the maximum height the particles position has been shown as [tex]\frac{R}{3}[/tex].
The given parameters;
mass of the particle, = Mradius of the particle, = Rmaximum height the particle attains = R/3The velocity of the particle is given as;
[tex]v^2 = \frac{GM}{2R}[/tex]
The total mechanical energy of the particle is given as;
[tex]-\frac{GMm}{R} + \frac{1}{2} mv^2 = - \frac{GMm}{R} + \frac{1}{2} mv^2[/tex]
At maximum height the final velocity of the particle is zero.
[tex]-\frac{GMm}{R} + \frac{1}{2} mv^2 = - \frac{GMm}{R +h}[/tex]
[tex]-\frac{GMm}{R} + \frac{1}{2} m\times \frac{GM}{2R} = - \frac{GMm}{R +h}\\\\-\frac{GMm}{R} + \frac{GMm}{4R} = - \frac{GMm}{R +h}\\\\- \frac{3GMm}{4R} = - \frac{GMm}{R +h}\\\\- \frac{3}{4R} = - \frac{1}{R+ h} \\\\3(R+ h) = 4R\\\\3R + 3h = 4R\\\\3h = 4R - 3R\\\\3h = R\\\\h = \frac{R}{3}[/tex]
Thus, at the maximum height the particles position has been shown as [tex]\frac{R}{3}[/tex].
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Please help with this question, it’s for physical science
Answer:
s times t
Explanation:
The equation for distance is D = st
Answer:
D is the correct answer (D=S*T)
This is an algebraic law; if you are to move the denominator or numerator to the other side of the equation, you must multiply it by the other side.
S=D/T is the same as D=S*T.
so distance=speed times time.
so if you are going 50 miles per hour, you multiply that times time, say one hour. you get your D distance which is 50 miles.
Need help on this thank you
Answer:
TRUE - In any collision between two objects, the colliding objects exert equal and opposite force upon each other. This is simply Newton's law of action-reaction.
A bowling ball, basketball, and tennis ball are all raised to the same height above the ground. Give the order of objects from the least potential energy to the most
Answer:
bowling ball, basket ball, tennis ball
Explanation:
four particles connected by rigid rods of negligible mass where y1 = 5.70 m. the origin is at the center of the rectangle. The system rotates in the xy plane about the z axis with and angular speed of 5.60 rad/s. a) calculate the moment of inertia of the system about the z axis. b) Calculate the rotational kinetic energy
The definition of moment of inertia and kinetic energy we can find the results for the questions are:
a) The moment of inertia is: I = 32.49 kg m²
b) The kinetic energy is: K = 509.4 J
a) The moment of inertia is a scalar quantity that has the same function as mass, it is given by
I = m r²
They indicate that the length of the bar is y₁ = 5.70 m, if the two rigid bars form the square that supports the masses, the distance from the center to the end where each mass is:
r = y₁ / 2
r = 5.70 / 2 = 2.85 m
The moment of inertia of the system is.
I = 4 m r²
Let's calculate.
I =4 m 2.85²
I = 32.49m kg m²
If we assume that the mass of each point particle is:
m = 1 kg
I = 32.49 kg m²
b) They ask for the rotational kinetic energy, if the angular velocity is.
w = 5.60 rad / s
The kinetic energy for rotational motion is.
K = ½ I w²
Let's calculate.
K = ½ 32.49 5.60²
K = 509.4 J
In conclusion with the definition of moment of inertia and kinetic energy we can find the results for the questions are:
a) The moment of inertia is: I = 32.49 kg m²
b) The kinetic energy is: K = 509.4 J
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Thinking Mathematically: Explore the quantitative dependencies of the acceleration upon the speed and the radius of curvature. Then answer the following questions. a. For the same speed, the acceleration of the object varies _____________ (directly, inversely) with the radius of curvature. b. For the same radius of curvature, the acceleration of the object varies _____________ (directly, inversely) with the speed of the object. c. As the speed of an object is doubled, the acceleration is __________________ (one-fourth, one-half, two times, four times) the original value. d. As the speed of an object is tripled, the acceleration is __________________ (one-third, one-ninth, three times, nine times) the original value. e. As the radius of the circle is doubled, the acceleration is __________________ (one-fourth, one-half, two times, four times) the original value. f. As the radius of the circle is tripled, the acceleration is __________________ (one-third, one-ninth, three times, nine times) the original value.
The expression for the centripetal acceleration allows to find the results for the questions are:
A) The acceleration varies INVERSELY with the radius of curvature.
B) The acceleration varies DIRECTLY with the speed.
C) The acceleration becomes four times greater.
D) The acceleration becomes nine times greater.
E) The acceleration is reduced to half.
F) The acceleration is reduced to a third.
In circular motion there must be an acceleration towards the center of the circle, it is called cenripetal acceleration, in this case all the energy supplied to the system is used to change the direction of the speed even when its magnitude remains constant.
[tex]a_c = \frac{v^2}{r}[/tex]
Where [tex]a_c[/tex] the centripetal acceleration, v is the speed and r the radius of curvature of the circle.
Now we can answer the questions about centripetal acceleration.
A) For the same speed, the acceleration varies INVERSELY with the radius of curvature.
B) For the same radius of curvature the acceleration varies DIRECTLY with the speed.
C) The speed is doubled
v = 2 v₀
[tex]a_c = \frac{(2v_o)^2 }{r}[/tex]
[tex]a_c = 4 \ \frac{v_o^2 }{r}[/tex]
The acceleration becomes four times greater than the original value
D) The speed is tripled
v = 3 v₀
[tex]a_c = 9 \frac{ v_o^2}{r}[/tex]
Acceleration becomes nine times greater than the original
E) the radius of curvature is doubled
r = 2 r₀
[tex]a_c = \frac{v_o^2}{2 r_o }[/tex]
[tex]a_c = \frac{1}{2} a_o[/tex]
Acceleration is reduced to half the original value
F) The radius of curvature is tripled
r = 3 r₀
[tex]a_c = \frac{v_o^2 }{3 r_o} \\ \\a_c = \frac{1}{3} a_o[/tex]
The acceleration is reduced to a third of the initial one.
In conclusion using the expression for the centripetal acceleration we can find the answers for the questions are:
A) The acceleration varies INVERSELY with the radius of curvature.
B) The acceleration varies DIRECTLY with the speed.
C) The acceleration becomes four times greater.
D) The acceleration becomes nine times greater.
E) The acceleration is reduced to half.
F) The acceleration is reduced to a third.
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A boy of mass 43.2 kg runs and jumps onto a stationary skateboard.The boy lands on the skateboard with a horizontal velocity of 4.10 m/s.The skateboard has a mass of 2.50 kg.
Using ideas about conservation of momentum, calculate the combined
velocity of the boy and skateboard just after the boy lands on it.
Answer:
= 3.87 m/s
Explanation:
Since momentum is conserved, momentum right before and after the boy jumps onto the skateboard should be the same.
Initial momentum = momentum of boy = 43.2 x 4.10 = 177 kg·m/s
Final momentum = momentum of boy and skateboard = (43.2 + 2.50) x v = 45.7v
177 = 45.7v
v = 177 / 45.7 = 3.87 m/s
(Hope this helps can I pls have brainlist (crown)☺️)
The combined velocity of the boy and the skateboard just after the boy lands on it will be equal to 3.87 m/s.
What is momentum?Momentum is the product of a particle's mass and velocity. Being a vector quantity, momentum possesses both direction and magnitude. According to Isaac Newton's second equation of motion, the force applied on a particle is equivalent to the temporal rate at which momentum changes.
According to Newton's second law, the product of the energy and the time interval is equal to the shift in momentum if a constant force acts on a molecule for a specified amount of time.
Momentum should be the same both before and after the boy gets onto the skateboard because it is preserved.
Initial momentum = momentum of boy
= 43.2 × 4.10 = 177 kg m/s
Final momentum = momentum of boy as well as skateboard
= (43.2 + 2.50) × v = 45.7 v
177 = 45.7 v
v = 177 / 45.7 = 3.87 m/s
Therefore, the combined velocity of boy and skateboard is 3.87 m/s.
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repost!! help need answer
Answer:
Ask a tutor it is tough
Ask tutor for your betterment
You are observing a star that is 250 million light years away. From the starlight you are observing now, the appears to be 30 million years old and you determine that the star has a lifetime of 120 million years. How long will it be until Earth receives light from the supernova that occurs at the end of the life of the star
What ever games your playing it wont work you cant defeat me hahhahha oh I know :O but he can AHHHH :D D: NOOOO IMPOSSIBLE.
Is my answer correct
Answer:
it right congratulations
Answer:
A
Explanation:
Simply option A is correct
It's a bit of a common sense question
At the highest point it's velocity will be automatically 0 since it is in rest and so is the acceleration
How can wind, coiled wire, and magnets be used together to generate electricity?
Answer:
b
Explanation:
hope helpful
have a great day
A mover pushes a 45 kg crate across a level floor with a force of 300 N, but the crate accelerates at a rate of only 4.44 m/s2 because a friction force opposes the crate's motion. What is the magnitude of this force of friction? 300 N Force of Friction O A. 50 N N OB. 25 N C. 15 N 0 D. 100 N
By Newton's second law, the net force on the crate is
∑ F = 300 N - f = (45 kg) (4.44 m/s²)
where f is the magnitude of friction. Solve for f :
300 N - f = (45 kg) (4.44 m/s²)
f = 300 N - (45 kg) (4.44 m/s²)
f = 100.2 N ≈ 100 N (D)
A massive launcher sends a projectile vertically upwards from the surface of a planet of mass M and radius R. You may assume that this planet has no atmosphere. Part A If the projectile is launched at the escape speed, how do the magnitudes of its initial KE and gravitational potential energy (GPE) compare
Answer:
It can be shown that the potential energy of an object at the surface of the planet would be -G M / R if the potential at infinity is chosen to be zero.
Kinetic energy of G M / R would be required for the escape speed of such an object. The total energy in all such cases is zero.
This can easily be seen by considering the speed of an object falling from infinity towards the planet - the total energy will remain zero if it was zero when the object started to fall.
The potential at infinity is set to zero while the kinetic energy will be [tex]\rm \frac{GM}{R}[/tex] and total energy will be zero.
What is escape speed?Escape speed is the minimum speed required for a free, non-propelled object to escape from the gravitational pull of the main body and reach an infinite distance from it in celestial physics.
It is proven that if the potential at infinity is set to zero, the potential energy of an item on the planet's surface is [tex]\rm \frac{-GM}{R}[/tex].
The escape speed of such an item would necessitate kinetic energy will be [tex]\rm \frac{GM}{R}[/tex]. In all of these circumstances, the total energy is zero.
Consider the speed of an item falling from infinity towards the planet: if the total energy was zero before the thing began to descend, the total energy will stay zero.
Hence the potential at infinity is set to zero while the kinetic energy will be [tex]\rm \frac{GM}{R}[/tex] and total energy will be zero.
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A chemical system is considered to have reached dynamic equilibrium when:__________.
a. the frequency of collisions between the reactant molecules is equal to the frequency of collisions between the product molecules.
b. the rate of production of each of the product species is equal to the rate of consumption of each of the reactant species. c. the rate of production of each of the products is equal to the rate of their consumption by the reverse reaction.
d. the sum of the concentrations of each of the reactant species is equal to the sum of the concentrations of each of the product species.
e. the activation energy of the forward reaction is equal to the activation energy of the reverse reaction.
Answer:
D
Explanation:
Sum of the concentrations of each of reactant species is equal to the sum of the concentrations of each of the product species
in a closed system of a cannon and cannonball, which changes would both results in an increase in the kinetic energy of the cannonball when fired from the cannon?
A) decrease the mass of the cannon or decrease the mass of the cannonball
B) increase the mass of the cannon or decrease the mass of the cannonball
C) decrease the mass of the cannon or increase the mass of the cannonball
D) increase the mass of the cannon or increase the mass of the cannonball
Changes that would results in an increase in the kinetic energy of the cannonball in a closed system, when it is fired from the cannon is B:increase the mass of the cannon or decrease the mass of the cannonball.
A closed system can be considered one that is not been affected by external forces. With the conservation of momentum, there would be collisions as well inexplosions.This explains that when a cannon is fired, there would be gain of forward momentum by the cannon ball, while the cannon experience backward momentum.For the kinetic energy of the cannonball to increase, when fired from the cannon, then the mass is the cannon would be increased or the mass of the cannonball would be decreased.
Therefore, option B is correct.
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If the law allows abortion based on sex, should we also allow abortion based on race, ethnicity, or skin color? Briefly explain why you believe this is right or wrong.
Answer:
No because you don't have to be black or white you don't have to be a pacific race to just get it like lets say for example a asian person come in and they want to get a abortion but the doctor say no then that person can end up killing her self or when the baby is born she could end you know doing something bad. But no you do not have to be a pacific person to just get it
Explanation:
25. Which of the following cannot be broken down into smaller parts through ordinary chemical means?
a. Nitrogen
b. Protein
C. Salt
d. Sugar
Answer:
the correct answer is sugar
The following question has two parts. First, answer part A. Then, answer part B.
Part A:
Why did the author most likely choose the title “Breaking Barriers” for this text?
A.
to show that Elizabeth worked hard to make people like her
B.
to show that Elizabeth accomplished things never done before
C.
to show that Elizabeth proved to be smarter than those around her
D.
to show that Elizabeth tried to show she was the better than other doctors
Part B:
Which sentences from the text best support your answer in part A? Select two options.
A.
“Elizabeth loved learning, and she developed a passion for reading.”
B.
“When Elizabeth was 11 years old, her family moved to America.”
C.
“When she was just 16, she became a teacher.”
D.
“Finally, the Geneva Medical College in New York accepted her as a student.”
E.
“When people in town ignored the woman with the strange ambition, Elizabeth treated them in a polite, quiet manner.”
F.
“She became the first woman in the country to obtain a medical degree.”
Answer:
for part A the answer is D and for part B the answer is F
HELPPPP
The maximum force of sliding friction between a 10 kg rubber box and the concrete
floor is 64 N. How much force should a worker push on the box with if he wants it to
move at a constant velocity?
1) A little less than 64 N
2)A little more than 64 N
3)Exactly 64 N.
4)Exactly 640 N
The force that will move the box at constant velocity must be a little more than 64 N.
The coefficient of sliding friction is obtained from the formula;
μ= F/R
Where;
F = frictional force
μ = coefficient of sliding friction
R = Normal reaction
It is necessary to note that the force that will move the body must be greater than the frictional force acting between the body and the surface in order to move the body. Hence, the force that will move the box at constant velocity must be a little more than 64 N.
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A double concave lens is a ________ lens, and a double convex lens is a ______ lens.
a.
converging, diverging
c.
converging, converging
b.
diverging, converging
d.
diverging, diverging
Answer:
b. diverging, converging
Answer:diverging, converging
Explanation: