Jessica stretches her arms out 0.60 m from the center of her body while holding a 2.0 kg mass in each hand. She then spins around on an ice rink at 1.1 m/s.
a. What is the combined angular momentum of the masses?
b. If she pulls her arms into 0.15 m, what is her new linear speed?
I'm really confused ab the explanations behind this. help, please
Answer:
a.) L = 2.64 kgm^2/s
b.) V = 4.4 m/s
Explanation: Jessica stretches her arms out 0.60 m from the center of her body. This will be considered as radius.
So,
Radius r = 0.6 m
Mass M = 2 kg
Velocity V = 1.1 m/s
Angular momentum L can be expressed as;
L = MVr
Substitute all the parameters into the formula
L = 2 × 1.1 × 0.6 = 1.32kgm^2s^-1
the combined angular momentum of the masses will be 2 × 1.32 = 2.64 kgm^2s-1
b. If she pulls her arms into 0.15 m,
New radius = 0.15 m
Using the same formula again
L = 2( MVr)
2.64 = 2( 2 × V × 0.15 )
1.32 = 0.3 V
V = 1.32/0.3
V = 4.4 m/s
Her new linear speed will be 4.4 m/s
The coldest layer of Earth’s atmosphere is the __________. a. troposphere c. mesosphere b. stratosphere d. thermosphere
Answer: c.mesosphere
Explanation: Temperatures can reach lows of -90 degrees Celsius in the mesosphere, making it the coldest layer of the earth's atmosphere. The mesosphere extends above the stratosphere and ranges from 50 km to 87 km above the surface.
Which property of sugar makes it different from white crystalline sand?
Answer:
The property of sugar which makes it different from sand is that sugar can dissolve in water. Explanation: however the power of dissolving of sand is not present. This is due to the presence of interaction between sugar and water.
Explanation:
I hope that was useful
What type of bond is most likely to form between atoms of the same element when the element is a metal?
Answer:Covalent bond
Explanation:
Calculate the volume of the part of the sphere that will be immersed in the mercury when the density of the sphere is 7800kg/metre cubic and volume of 136centrimetre cubic and the density of the mercury is 13600kg/metre cubic
Answer:
78 cm³
Explanation:
The Volume Immersed = (density of object/ density of fluid) x Volume of Object
Vi = (7800/13600) x 136 = 78 cm³
Which of the following represents the equation of motion of a steel ball thrown into a viscous liquid when it is moving with an acceleration a ?(A) W-V-U=ma (B)W-U=ma-V (C)W-U-V=0 (D)U-V=W
Answer: A
Explanation: When a steel ball is thrown into a viscous liquid, three forces will act on the ball.
1.) The viscous drag force V which is acting upward
2.) The buoyant force U which is acting upward and
3.) The weight of the ball W. Which is acting downward.
When it is moving with an acceleration a, the weight W will be greater than U and V
Since Force = ma.
The resultant vector force will be
W - V - U = ma
a loop with a break in it that prevents current form flowing is called a(n) blank circuit
Answer: it is called a open circuit
Explanation:
I NEED HELP PLEASE, THANKS!
Find or draw at least two pictures that illustrates Newtons first Law. Write a paragraph describing how each of the pictures you choose illustrates the law.
Explanation:
When a person is standing still, the forces acting on them (weight force pulling down and normal force pushing up) are equal and opposite, so the net force is balanced. So the person will continue to be at rest, unless the net force becomes unbalanced.
When a person falls with a parachute, the forces acting on them (weight force pulling down and air resistance pushing up) are equal and opposite, so the net force is balanced. So the person will continue to fall at the same speed until the net force becomes unbalanced.
What happens to the Kinetic Energy of an object if its mass stays the same but its speed is doubled
Answer:
kinetic energy is proportional to the velocity squared, increases in velocity will have an exponentially greater effect on translational kinetic energy. Doubling the mass of an object will only double its kinetic energy, but doubling the velocity of the object will quadruple its velocity.
pls mark as branliest
A right triangle ABC has sides /AB/ =9cm, /BC/=12cm find /AC/ and angles ACB and ABC if angle BAC= 90°
fdi9bn 08989089089008i uuuuuuri9ij
All matter is made up of________ called atoms or molecules
A ball is thrown at a wall with a velocity of 5 m/s and bounces off at 4 m/s as shown in the diagram. If the impulse provided by the wall is 3 Nm, then what is the mass of the ball?
Answer:
m = 3 kg
Explanation:
It is given that,
Initial speed of a ball is 5 m/s, u = 5 m/s
Final speed of a ball is 4 m/s, v = 4 m/s (as it bounces)
Impulse provided by the wall is -3 N-m (impulse is provided in opposite direction)
We need to find the mass of the ball. Impulse provided to an object is given by the change in its momentum as :
J = m(v-u)
m is mass of the ball
[tex]m=\dfrac{J}{(v-u)}\\\\m=\dfrac{-3}{(4-5)} \\\\m=3\ kg[/tex]
So, the mass of the ball is 3 kg.
I NEED HELP PLEASE, THANKS! Describe each Newton Law. :)
Explanation:
1st- states that when two bodies interact, they apply forces to one another that are equal in magnitude and opposite in direction.
2nd- states that the time rate of change of the momentum of a body is equal in both magnitude and direction to the force imposed on it. (most important law)
3rd- states that when two bodies interact, they apply forces to one another that are equal in magnitude and opposite in direction. (law of action/reaction)
Resistance and resistivity are related by a: 1.factor that is dependent on the length of the material 2.factor that is dependent on the area of the material 3.proportionality constant dependent on the identity of the material 4.proportionality constant dependent on the source of the material
Answer:
1. factor that is dependent on the length of the material.
2. factor that is dependent on the area of the material
Explanation:
Resistance R is directly proportional to its length L of an object and it is inversely proportional to the crossectional area of that object.
Mathematically, this is represented as:
a) Resistance R is directly proportional to its length L of an object
R ∝ L ......... Equation 1
b) Resistance R is inversely proportional to the crossectional area (A) of an object
R ∝ 1/A ............ Equation 2
Combining the two equations together, we have:
Resistance R is directly proportional to its length L of an object
R ∝ L/A .......... Equation 3
Resistivity of a material is the natural or inherent or intrinsic property that a material has. The Resistivity of a material is not dependent on the length or crossectional area of such material. It is only temperature dependent.
The resistance of a material is also dependent on the resistivity of the material. This means the resistance of a material is directly proportional to the resistivity of the material.
R ∝ ρ........Equation 4
Combining Equation 4 and 3 together, we have:
R = ρL/A
Where:
R = Resistance
ρ = Resistivity
L = Length of the material
A = Crossectional area of the material
Resistance and resistivity are related by a factor that is dependent on the length of the material a factor that is dependent on the area of the material
I NEED HELP PLEASE, THANKS! :) Why is it a good idea to touch a metal pole, or similar conductor, before filling up a car with gas?
Answer:
While filling up the gas, a static discharge can take place which is really dangerous for us. It can even ignite a fire at the gas station. Touching the metal pole or any conductor will pass all of the charge into the Earth and thus we'll keep safe.
Answer:
It is a good idea to touch a metal pole or similar conductor before filling up a car with gas because it will discharge any static electricity on you, making it safer for everyone.
Explanation:
Las esferas metálicas que se muestran en la figura se cargan con 1C cada una. La balanza se equilibra al situar el contrapeso a una distancia x del eje Se pone una tercera esfera a una distancia 2d por debajo de a esfera A y cargada con -2C. Para equilibrar la balanza se debe mover el contrapeso a la derecha, porque?
Answer:
this relationship to be true the value x ’must be positive, so it must move to the right.
Explanation:
En este ejercicio debemos utilizar la relacion de equilibrio rotacional.
Fijemos un sistema de referencia situado en el eje de jiro del sistema y la rotación antihoraria es positiva.
Las esferas estan a la izquierda y el contrapeso ala derecha
W d = w_contrapeso x
donde W es el peso de las esferas de d su distancia hasta eleje de giro
Ahora colocamos la carga negativa debajo de la esfera A, como las cargas son de diferente signo las dos esferas se atraen, lo que crea una fuerza hacia bajos de magnitud
F =k q₁ q₂/r²
F =8,9 10⁹ 1 2/ (2d)²
F = 4,45/d² N
volvamos escribir la ecuación de equilibrio rotacional con esta fuerza
F d + W d = W_contrapeso (x+x’)
(4,45 10⁹ /d²) d + W d = W_conrapeso x+ W contrapesos x’
en la primera ecuación vimos que dos terminos se igualan ,por lo cual se anulan quedando
4,45 10⁹/d = W contrapeso x’
para que esta relación sea cierta el valor e x’ debe ser positivo, por lo cual debe moverse a la derecha.
Traduction
In this exercise we must use the relationship of rotational equilibrium.
Let's fix a frame of reference located on the system's axis of rotation and the counterclockwise rotation is positive.
The spheres are on the left and the counterweight on the right
W d = w_counterweight x
where W is the weight of the spheres of d its distance to the turning axis
Now we place the negative charge under sphere A, as the charges are of different sign the two spheres attract, which creates a downward force of magnitude
F = k q₁ q₂ / r²
F = 8.9 10⁹ 1 2 / (2d)²
F = 4.45 / d² N
let's rewrite the rotational equilibrium equation with this force
F d + W d = W_ counterweight (x + x ’)
(4.45 10⁹ / d²) d + W d = W_counterweight x + W counterweights x’
In the first equation we saw that two tenunos are equal, which is why they cancel, leaving
4.45 10⁹ / d = W counterweight x ’
for this relationship to be true the value x ’must be positive, so it must move to the right.
If an object absorbs energy at the same rate as it gives off energy, then __________.
Answer:
The temperature remains constant
Explanation:
From the radiation law, the net energy radiated P = Power radiated - Power absorbed
Now, let the body be at a temperature T₁ above its surroundings, the rate at which energy is given of is P₁ = σεAT₁⁴
let T₂ be the temperature of its surroundings, the rate at which energy is absorbed is P₂ = σεAT₂⁴
The net energy radiated (Power radiated) P = P₂ - P₁ = σεAT₂⁴ - σεAT₁⁴ = σεA(T₂⁴ - T₁⁴)
Now, if the object absorbs energy at the same rate it gives off energy, P₁ = P₂ and P = 0.
So, σεA(T₂⁴ - T₁⁴) = 0
Since σεA ≠ 0 then (T₂⁴ - T₁⁴) = 0 ⇒ T₂ = T₁
Since there is no temperature difference, the temperature of the object remains constant.
A diverging lens of focal length 18.0m is used to view a shark that is 90.0m away from the lens. If the image formed is 1.0m long, calculate the: (i) image distance; (ii) length of the shark.
Answer:
i. + 22.5 m ii. 4.0 m
Explanation:
i. Image distance
Using the lens formula
1/u + 1/v = 1/f where f = focal length = + 18.0 m, u = object distance = distance of shark away from lens = + 90.0 m and v = image distance from lens = unknown
So, we find v
1/v = 1/f - 1/u
= 1/+18 - 1/+90
= (5 - 1)/90
= 4/90
v = 90/4
= + 22.5 m
So the image is real and formed 22.5 m away on the other side of the lens.
ii Length of Shark
Using the magnification formula, m = image height/object height = image distance/object distance. image height = 1.0 m where object height = length of shark.
m = image distance/object distance
= v/u
= +22.5/+90
= 0.25
0.25 = image height/object height
So,
object height = image height/0.25
= 1.0 m/0.25
= 4.0 m
So, the length of the shark is 4.0 m
A train starts from rest .It moves through 1km in 100s with uniform accelaration . What will be its speed at the end pf 100 s
Answer:
Explanation:
Distance = 1 km
= 1000m
Time = 100 sec
Speed = distance / time
= 1000 / 100
= 10 m/s
a solid weighs 18.36N on the surface of the moon. The force of gravity on the moon is 1.7Nkg-1. Determine the mass of the solid
Answer:
mass of the solid is 10.8kg
Explanation:
Weight of the solid=w=18.36N
Force of gravity on the surface of the moon=g=1.71Nkg^-1
Mass of the solid on the moon=m=?
as we know that
weight=mass×force of gravity
here we have to find the mass
[tex]\frac{weight}{force of gravity}[/tex]=mass
mass=[tex]\frac{18.36N}{1.7Nkg^-1}[/tex]
Mass of the solid=10.8kg
i hope it will help you
HELLLP PLEASE || the graph below shows a conversion of energy for a skydive jumping out of a plane and landing safely on the ground. which energy is represented by line A? A) Potential B) Thermal C) Kinetic D) Total Energy
Answer: I maybe wrong but i'm pretty sure its C) Kinetic energy
A 4400 W motor is used to do work. If the motor is used for 200 s, how much work could it do? (Power: P = W/t) 22 J 4200 J 4600 J 880,000 J
Answer:
880,000 J
Explanation:
P = W/t
4400 W = W / 200 s
W = 880,000 J
Answer:
880,000 J
Explanation:
e)
The surface area of foot of Bimaba is 150cm? If she weighs 50kg,
how much pressure does she exert on the ground, as she stands on
her one foot? (32666.67 pa)
Answer:
Pressure, P = 32666.66 Pa
Explanation:
It is given that,
Surface area of foot of Bimaba is 150 cm² or 0.015 m².
Her weight is 50 kg
We need to find the pressure does she exert on the ground, as she stands on her one foot. The force acting per unit area is called pressure. It can be given by :
[tex]P=\dfrac{F}{A}\\\\P=\dfrac{mg}{A}\\\\P=\dfrac{50\times 9.8}{0.015}\\\\P=32666.66\ Pa[/tex]
So, the pressure is 32666.66 Pa.
A gas baloon bursts when comes to a high altitude.... Plss answer it
Answer:yess
Explanation:as weather balloons travels from the earth's surface, the air pressure around ballons decreases slowly.As the air gets thinner,the gallons casing gets tighter.
This is due to gas expanding within balloon.The expanding gas causes the balloons to reach maximum height and it burst.
You have a graduated cylinder that you use to measure volume. The cylinder
is marked in 1 ml increments. Which measurement made using this cylinder
contains the correct number of significant digits?
A. 35.5 ml
B. 320.01 ml
C. 75.333 ml
D. 21 ml
Answer:
35.5 ml
Explanation:
The other guy made me get the question wrong lol here ya go good luck
Which is an example of a fission reaction? Check all that apply.
H + H → He 2n
+
239 Pu + n + 1904 Ce + Kr + 2n
295 Am + in → 154 La + 95 Sr + 3 in
13C + H + 4N
Answer:
Check Explanation
The fission reactions include
239 Pu + n → Ce + Kr + 2n
And
295 Am + in → 154 La + 95 Sr + 3 n
Explanation:
A fission reaction is a radioactive reaction in which an atom with a heavy nuclei splits into atoms with smaller or lighter nuclei usually brought about by the attack of a fundamental particle and accompanied by the release of some fundamental particles (neutrons mostly) and energy.
Although, the reactions to be examined aren't totally clear, we can still guess which element is which and know which of the reactions has a heavier nuclei splitting into smaller ones.
1) H + H → He + 2n
Two hydrogen atoms combine to give an helium atom and release neutrons too, showing that here, smaller molecules combine to form a bigger one. Hence, this isn't a fission reaction, rather, it's a fusion reaction.
2) 239 Pu + n → Ce + Kr + 2n
Here, Pu (Plutonium, atomic mass 239), a heavy nuclei that splits into smaller nuclei, Ce (Cerium, atomic mass 140) and Kr (Krypton, atomic mass 84) together with some neutrons to fit the definition of a fission reaction. Hence, this reaction is a fission reaction.
3) 295 Am + n → 154 La + 95 Sr + 3 n
Here, Pu (Americium, atomic mass 295), a heavy nuclei that splits into smaller nuclei, Ce (Lamthanium, atomic mass 154) and Sr (Strontium, atomic mass 95) together with some neutrons to fit the definition of a fission reaction. Hence, this reaction is a fission reaction.
4) 13C + H → 14N
Carbon 13 combines with a hydrogen element to mutate and give nitrogen-14, a heavier nuclei, showing all signs of a nuclear fission and not fission.
Hope this Helps!!!
Answer:
b and c
Explanation:
got it correct on edg
A ray diagram is shown what does the letter x represent?
Answer: angle of incidence
Answer:
A) angle of incidence
Explanation:
Place the types of radiation in order of INCREASING mass.
Answer & explanation:
Gamma Radiation (γ): Also called gamma rays. Gamma radiation is made of electromagnetic waves, has zero charge and mass, continuously emits heat and has the ability to ionize air and make it conductive of electric current. Beta radiation (β): Beta rays or beta particles, are electrons, negative particles with charge - 1 and mass number 0.Alpha radiation (α): Also called alpha particles or alpha rays, are particles charged by two protons and two neutrons. They have positive charge +2 and mass number 4.I NEED HELP PLEASE, THANKS :) What does it mean when white light is diffracted and at a particular location the color seen is blue?
Answer:
This is because white light consists of 7 colours with different angles o deviation or retraction.
Explanation:
When a narrow beam of light is refracted by a prism the light spreads into a band of colours (called the spectrum of light )
But in this case if a blue colour is observed it is due to the angle of refraction ,for instance red is refracted the least and hence is seen
Answer:
When while light is diffracted and at a particular location blue color is seen, this means that blue color is reflected while all other colors will be absorbed. When the blue color is seen denotes the shortest wavelength being reflected and all other being absorbed at the specified location.
Find the average velocity if the takeoff velocity of an airplane on a runway is 300 km/hr with an acceleration of 1 m/s2 . A) 30 sec B) 41.7 sec C) 72.2 sec D) 83.33 sec
Answer:
83.33s
Explanation:
velocity=300km/hr ,acceleration =1m/s2
But before we can make this calculation,we have to make sure that both the acceleration and velocity are in the same units.So I decided to Chang the velocity to m/s.
Converting 300km/hr into m/s;
Changing 300km into m=300000m
Changing 1hr into secs=3600sec
Velocity in m/s=83.33m/s
But Time =velocity/acceleration
=83.33/1
=83.33sec
You have to decide what you want. Your question says "Find the average velocity", but the choices you listed are all times, not velocities.
(300 km/hr) x (1 hr / 3600 sec) = 83.33 meters/sec
-- If the airplane starts from rest and accelerates uniformly at 1 m/s², it'll take 83.33 seconds to reach takeoff speed.
-- If it starts from rest and accelerates uniformly to 83.33 m/s, then its average speed is 41.67 m/s no matter what its acceleration may be.