*Sorry for the bad quality picture!*
A frictionless pendulum with a mass of 0.4 kg and a length of 2.1 m starts at point A, at an angle 0 of 60°. As it swings downward, it passes through point B, which is 30 degrees from equilibrium. What is the kinetic energy of the pendulum at point B?
A) 3.9 J
B) 3.0 J
C) 1.1 J
D) 4.1 J
Answers
The conservation of mechanical energy allows finding the result for the speed of the pendulum when it is at 30º is:
The speed is: 3.88 m / s
The conservation of mechanical energy is a theorem of greater importance in physics and ordinary life, it states that if there is no friction force the total mechanistic energy remains constant at all points.
Mechanical energy is the sum of kinetic energy plus all potential energies. In the attachment we see a diagram of the pendulum's movement at the two points of interest.
They indicate that the pendulum is released from an initial angle of θ₁ = 60º, let's find the mechanical energy at that point.
Em₀ = U = m g h
Where the height is measured from the lowest point of the movement.
h = L - L cos tea1 = L (1 cos tea1)
The second point of interest occurs for θ₂ = 30º.
At this point part of the energy is indica and part gravitational potential.
[tex]Em_f[/tex] = K + U₂
[tex]Em_f[/tex] = ½ m v² + m g h ’
There is no friction in the system, therefore mechanical energy is conserved.
Em₀ = Em₀_f
mg L (1 - cos θ₁) = ½ m v² + m g L (1 - cos θ₂)
v² = 2g L (cos θ₂ - cos θ₁)
Let's calculate.
v² = 2 9.8 2.1 (cos 30 - cos 60)
v² = 41.16 0.366
v = 3.88 m / s
In conclusion using the conservation of mechanical energy we can find the result for the speed of the pendulum when it is at 30º is:
The speed is: 3.88 m / s
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Answer:
3.0 J
Explanation:
Just took the test
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actually answer plauto
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a.
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c.
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in a collision, a 25.0kg mass moving at 3.0m/s transfers all of its momentum to a 5.0kg mass. What is the velocity of the 5.0kg mass after the collision?
Answers
Answer:
Explanation:
The 25.0 kg mass has momentum before the collision of
p = 25.0(3.0) = 75 kg•m/s
If all this momentum gets transferred into a 5.0 kg mass, the velocity of the 25.0 kg mass will be zero and the velocity of the 5.0 kg mass will be
75 / 5.0 = 15.0 m/s
Getting this to occur will require an addition of a significant amount of energy via an internal explosion or release of spring potential energy. This can be shown by looking at kinetic energies.
Initial system kinetic energy is ½(25.0)3.0² = 112.5 Joules
After the collision, system kinetic energy is ½(5.0)25² = 1,562.5 Joules
so 1562.5 - 112.5 = 1450 Joules of energy must be released during the collision to complete this scenario.
The most efficient energy transfer without energy release is an ideal elastic collision. Had these two masses been in such a collision with the given initial conditions, the 5 kg mass would have moved away at 5.0 m/s taking with it 5(5) = 25 kg•m/s of momentum leaving the 25 kg mass with 75 - 25 = 50 kg•m/s of momentum and a velocity of 50/25 = 2.0 m/s. Both masses are now traveling in the same direction as the original velocity, but at different speeds. Notice kinetic energy is conserved in elastic collisions
½(25)2² + ½(5.0)5² = 112.5 Joules.
The only time one mass can transfer its entire momentum to another mass without additional energy addition or subtraction is when the two colliding masses are identical in magnitude. Think pool balls colliding on a table.
electromagmetic radiation comes in different forms which pair does not appear next to one an other in the electromagmetic spectrum
A. microwaves, ultraviolet
B. x-rays,ultraviolet
C. visible light,infra-red rays
D. radio waves , microwaves
Answers
Answer:
A) microwaves and ultraviolet
Explanation:
this is the spectrum in order:
radio waves
microwaves
infra red
visible light
ultraviolet
X rays
gamma rays
Each substance has a unique set of properties that depends on the kinds of atoms it has and how the atoms are connected, or bonded. Bonding is related to the electrons in an atom, and there are different kinds of bonds. As a result, some substances can have the same atoms but different bonds. Substances that are different but have the same atoms are called allotropes. Allotropes have very different properties.
Diamond and graphite are well-known allotropes. Graphite is used in pencils for writing and is sometimes called lead. Diamond is colorless and transparent, and is one of the hardest substances known. Graphite is dark gray and soft. When we write, layers of graphite easily transfer from the pencil to the paper. Although they’re different, diamond and graphite each only contain one kind of atom—carbon.
How do you think the bonds between carbon atoms might be different in diamond and graphite? Use household materials to build physical models to help you develop your ideas. Describe what you learned from your models. What other kinds of allotropes are there? What kinds of properties and atomic bonds do they have?
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Answer:
C - the atom is all about the proton number.
An isotope of an atom is the same element with a different number of neutrons.
Explanation:
A............... pulley helps us by changing the direction of the applied effort
Answers
Answer/Explanation:
True
A fixed pulley changes the direction of the force you exert by pulling, so you can pull down to move an object up. In this fixed pulley system, you pull down on one side of the rope and the other side goes up. You use the same amount of force to pull down as you would to lift the toy yourself.
A 500-kg golf cart is moving on level ground in a circular path of radius 10 m with a speed of 12 m/s. What is the centripetal force acting on the cart?
Answers
Answer:
7200N
Explanation:
Centripetal force is directly proportional to the product of the mass and the square of the velocity and inversely proportional to the radius given.
real answers only pls
Answers
Answer:
1. it spins
2. falls in a curve
3. falls flat on the floor
How are acceleration and velocity related
A: An object with constant velocity also has constant acceleration
B: Acceleration and velocity are not related. C:Acceleration describes how fast the velocity of an object is changing,
D: Acceleration only occurs when the speed of an object changes, but velocity can change if speed or direction changes
Answers
Answer:
answer is C
Explanation:
acceleration is rate of changing velocity in a time
name a substance which will undergo change E
Answers
Answer:
Water
Explanation:
At 0 degrees it's solid...Then it melts into a liquid and at 100 degrees it's gas Simple
HELP!!! I HAVE NO IDEA!!!!!!!!!!!!!
1. A rocket has a mass of 0.8 kg and an engine that provides 100 N of force. A second rocket is being designed to use the same engine but accelerate at half the rate of the first rocket. What is the mass of the second rocket?
a. 0.4 kg
b. 1.6 kg
c. 2.4 kg
d. 0.8 kg
2. Which of the following would be a situation with unbalanced forces?
a. Two people pulling on the same side of a wheelbarrow
b. A team of players in tug of war pulling on the rope, each team with equal numbers of people pulling with equal strength
c. Two people of opposite sides of a big tire. One pushes the tire and one pulls it with equal force
d. Two people not touching a crate that is sitting stationary.
3. Why is it generally easier to push a heavy object that is already moving instead of the same heavy object that is stationary
a. The force of gravity on the object is different if it is stationary or not.
b. The force of friction on the object is different if it is stationary or not
c. The force of the push on the object is different if it is stationary or not
d. The normal force on the object is different if it is stationary or not.
Thanks In Advance!! (I will mark brainliest) :)
Answers
Answer:
Explanation:
The engine should create the same force
1) F = ma
F = M(½a)
therefore
ma = ½Ma
m = ½M
M = 2m
M = 2(0.8)
M = 1.6 kg
2) Unbalanced forces
a. Two people pulling on the same side of a wheelbarrow
c. Two people of opposite sides of a big tire. One pushes the tire and one pulls it with equal force
3) b. The force of friction on the object is different if it is stationary or not
Which phrase describes an irregular galaxy O has a round shape O does not have a specific shape O has arms that extend from the center O is larger than other types of galaxies
Answers
Answer:
I think it does not have a specific shape
Explanation:
Irregular galaxies have no definite shape, which means that the second option is correct. They are definitely not round.
The "spiral galaxy" is the type of galaxy that has arms that extend from the center. These arms look "spiral," which influenced its name.
They are actually smaller than the other types of galaxies. This makes them prone to collisions.
The phrase that describes the irregular galaxy is that it does not have a specific shape. The correct option is B.
What is irregular galaxy?A galaxy with an undefined shape is an irregular galaxy with a large number of young stars and a large amount of gas and dust that is typically found near larger galaxies.
An irregular galaxy is a catch-all term for any galaxy that does not neatly fit into one of the Hubble classification schemes.
They have no discernible shape or structure and could have formed as a result of collisions, close encounters with other galaxies, or violent internal activity.
They lack beautiful spiral arms, but they do have dark patches of gas and dust. Some irregular galaxies appear to be the result of two galaxies colliding.
Thus, the correct option is B.
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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.
Answers
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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if two masses 5.2kg and 4.8kg are attached to ends of inextensible string passed over a friction less pulley then acceleration of system
Answers
Answer:
If two masses 5.2 kg and 4.8 kg are attached to the ends of inextensible strings passed over a frictionless pulley then the acceleration of system is 0.4 ms-2.
Explanation:
Starting at 9a.m., you ride your hover board for 3hrs at an average speed of 6 mph. Out of breath, you stop for tea from noon until 2p.m. What is your average speed over the interval from 9a.m. to 2p.m.?
Answers
hope this helps!
A flea can jump with an initial velocity of 2.2 m/s at an angle of 21° with respect to the
horizontal.
Answers
Answer:
Explanation:
If no one can see it because the lights were out. Did the flea really jump?
What do you want here?
Max height (2.2sin21)²/ 2(9.8) = 3.2 cm
Time of flight 2(2.2sin21)/ (9.8) = 0.16 s
distance of flight (2.2cos21)(0.16) = 33 cm
what is one measurement needed to calculate the speed of an object
Answers
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:
How long will it take to travel 200 000 m [North] traveling 10 m/s
Answers
Answer:
there are 1,000m in a km, so 200km is 200,000m
200,000m/10m/s = 20,000s
Explanation:
Please mark me Brainlyest
The box is pushed to the left with 30 N of force, but does not move. What is the Friction Force?
Answers
However here coefficient of friction is not given so unable to calculate.
You can calculate it by below formula.
The formula given by
[tex]\\ \sf\longmapsto F_f=\mu N[/tex]
Or
[tex]\\ \sf\longmapsto F_f=\mu mg[/tex]
u is coefficient of friction
N is normal reaction.
Here..
box doesn't move means the force if limiting friction is greater than applied force.
A 12.0-g bullet is fired horizontally into a 112-g wooden block that is initially at rest on a frictionless horizontal surface and connected to a spring having spring constant 149 N/m. The bullet becomes embedded in the block. If the bullet-block system compresses the spring by a maximum of 83.5 cm, what was the speed of the bullet at impact with the block
Answers
PHYSICISTS NEEDED, THANK YOU, (10 POINTS)
Answers
Answer:
would it be 2.66666666667 or 2.7
Explanation:
A player kicks a soccer ball.
What is the reaction force?
A. The ball pushes back on the player's
foot.
B. The ground pushes back on the player.
C. The ground pushes back on the ball.
Answers
Answer:
the ground pushes back on the player
Answer:
c
Explanation:
force is every where so anything that goes up must come down
10. The SI unit of the solid angle is
a) Degree
b) Steradian
c) Revolution
d) Radian
Answers
The S.I unit of solid angle is steradian, or square radian (symbol: sr).
I WILL MARK BRAINLIEST !! PLEASE HELP!
Answers
Answer:
b
Explanation:
The model represents a fluorine (F) atom. What is the mass of the atom?
Answers
Answer:
19
Explanation:
The mass of an atom is found in the nucleus: number of protons + number of neutrons; 9 + 10 = 19
The mass number of fluorine is 19
A block slides down an incline plane that makes a 30 degree angle with the
horizontal. If the coefficient of kinetic friction is 0.3. Calculate the acceleration of the block.
Answers
Hi there!
We know that:
Force due to gravity = Mgsinθ
Force due to friction = μMgcosθ
Let the positive direction be directed in the direction of the block's acceleration, which is downward.
Thus:
ΣF = Mgsinθ - μMgcosθ
Solving for acceleration requires diving all terms by the mass, so:
a = gsinθ - μgcosθ
Substitute in given values. (g = 9.8 m/s²)
a = 9.8sin(30) - 0.3(9.8)cos(30) = 2.354 m/s²
Bill is sitting on a tree limb that is 4 meters above the ground with a water balloon. He wants to drop the water balloon so that it falls on his friend Tim who is approaching on a bike at a constant speed of 8 meters per second. How far away should Tim be from a point directly under bill when bill drops the balloon?
Answers
Answer:
wow poor bill
Explanation:
A man with a mass of 60 kg rides a bike with a mass of 13 kg. What is the force needed by the man to accelerate the bike at 0.90 m/s2?