A skater is spinning with his arms outstretched. He has a 2 lb weight in each hand. In an attempt to change his angular velocity he lets go of both weights (by just opening his grip). Does he succeed in changing his angular velocity
Answer:
No
Explanation:
Changing momentum of any kind requires work. Work is a force acting over a distance. While holding the weights at arms length and spinning will create a force (centripetal), there is no radial distance change incurred. Releasing the weights will reduce the force to zero, still no work done and no change in angular momentum.
If he was holding the weights at arms length while spinning and he pull his hands to his chest, there now exists both the centripetal force and a distance in the direction of that force (inward radial) this work will result in an increase in angular velocity as moment of inertia has decreased with the work done.
No, the skater doesn't succeed in changing his angular velocity.
Conservation of angular momentumThe final angular velocity of the skater is determined by applying the principle of conservation of angular momentum as shown below;
Li = Lf
[tex]Ii\omega _i = I_f \omega _f[/tex]
where;
Ii is the initial moment of inertia of the skaterIf is the final moment of inertia of the skaterωi is the initial angular speed of the skaterωf is the final angular speed of the skaterWhen the skater holds the weight, the momnet of inertia of both arms is the same. Also when the skater drops the weight, the moment of inertia of both arms is still the same. Thus, at any instant, the moment of inertia of the two arms is the same.
To change the angular speed, the initial and final moment of inertia of the two arms must be different. Thus, the skater doesn't succeed in changing his angular velocity.
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Peregrine falcons, which can dive at 200 mph (90 m/s), grab prey birds from the air. The impact usually kills the prey. Suppose a 480 g falcon diving at 75 m/s strikes a 240 g pigeon, grabbing it in her talons. We can assume that the slow-flying pigeon is stationary. The collision between the birds lasts 15 ms.
Answer:
What is the average force of collision?
Explanation:
The velocity of the combined mass after impact is found by conservation of momentum
0.480(75) + 0.240(0) = (0.480 + 0.240)v
v = 50 m/s
An impulse results in a change of momentum
FΔt = mΔv
F = mΔv/Δt
for the pigeon
F = 0.240(50 - 0)/0.015
F = 800 N
for the falcon
F = 0.480(50 - 75)/0.015
F = -800 N
The final speed(v) of the Peregrine falcons and pigeon is 50 m/s
The objective of this question is to determine the final speed(v) of the Peregrine falcons and pigeon
From the information given:
the mass of the falcon m_f = 480 gthe speed of the falcon v_f = 75 m/sthe mass of the pigeon m_p = 240 gthe collision time = 15 ms = 0.015 sAccording to the conservation of momentum, we can say that the totality of momentum before and after the collision is the same. As such;
[tex]\mathbf{m_fv_f = (m_f+m_p) v}[/tex]
[tex]\mathbf{480 g \times 75 m/s = (480 + 240) \ g \times v}[/tex]
[tex]\mathbf{v = \dfrac{480 g \times 75 m/s}{(480 + 240) \ g}}[/tex]
[tex]\mathbf{v = \dfrac{36000 \ m/s}{ 720}}[/tex]
v = 50 m/s
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What is speed of sound in air?
Answer:
speed of sound, speed at which sound waves propagate through different materials. In particular, for dry air at a temperature of 0 °C (32 °F), the modern value for the speed of sound is 331.29 metres (1,086.9 feet) per second
Wrte down the effect of humidity and temperature in the speed of sound....
Explanation:
the speed of sound is affected by temperature and humidity
Children in a tree house lift a small dog in a basket 3.85 m up to their house. If it takes 201 J of work to do this, what is the combined mass of the dog and basket
Answer:
Explanation:
The work will equal the increase in potential energy.
PE = mgh
m = PE/gh = W/gh = 201/(9.81(3.85)) = 5.32 kg
Is electrical energy the same or different from energy it takes to play a soccer game
Answer:
Diffrent
Explanation:
Electrical energy is electrical charges moving. When you play soccer kinetic energy is used. Kinetic energy is the movement of atoms, objects, and electrons.
An airplane accelerates down a runway at 3.20 m/s2 for 32.8 s until is finally lifts off the ground. Determine the distance traveled before takeoff.
Answer:
The distance traveled before takeoff is 1720 m
Explanation:
Given:a = + 3.2 m/s²
t = 32.8 s
Vᵢ = 0 m/s
To Find:d = ?
Now,
d = Vᵢ × t + 0.5 × a × t²
d = (0 m/s) × (32.8 s) + 0.5 × (3.20 m/s²) × (32.8 s)²
d = 1720 m
Thus, The distance traveled before takeoff is 1720 m
-TheUnknownScientist 72
A father (75 kg) was standing watching TV, minding his own business when one of his kids (20 kg) approached him at 2m/s heading at 0 degrees and jumped onto his back. Another kid (15 kg) approached him at 3m/s heading at 45 degrees to the first kid and also jumped on him at exactly the same time. Immediately after impact, in what direction did the group go (measured in degrees with respect to the first kid)
Answer:
Explanation:
Conservation of momentum
Let's say the first child was headed north
North momentum
75(0) + 20(2) + 15(3sin45) = (75 + 20 + 15)vn
vn = 0.6529 m/s
East momentum
75(0) + 20(0) + 15(3cos45) = (75 + 20 + 15)ve
ve = 0.28927 m/s
θ = arctan(0.28927/0.6529)
θ = 23.896...
θ = 24° east of north
(f) As the pions move away from each other, the ratio of the absolute value of electric potential energy to the final total kinetic energy of the two pions changes. At some point, the potential energy becomes negligible compared to the final total kinetic energy . We can consider that the value of the ratio is about 0.01 when , where is the final total kinetic energy of the two pions. What will the distance, , between the pions be when this criterion is satisfie
The distance r between the pions when the criteria are satisfied is 1.45 × 10⁻¹⁶ m
If we consider the potential energy (U) between the pions, then (U) can be expressed as:
[tex]\mathbf{U = \dfrac{kq^2}{r} ---- (1)}[/tex]
Given that at some instance, the potential energy becomes negligible compared to the final K.E.
As such the conservation of the total energy in the system can be given as:
E = U + KAgain, if we consider the ratio of the potential energy to the kinetic energy to be about 0.01, then:
[tex]\mathbf{\dfrac{U}{K}= 0.01} \\ \\ \mathbf{U = 0.01 K----(2)}[/tex]
∴
Equating both equations (1) and (2) together, we have:
[tex]\mathbf{\dfrac{kq^2}{r} = 0.01 K}[/tex]
[tex]\mathbf{\dfrac{kq^2}{r} = 0.01 \Bigg [ m_{o \pi}c^2 \Big [\dfrac{1}{\sqrt{1 - \dfrac{v_{\pi}^2}{c^2} }} \Big ] \Bigg] }[/tex]
[tex]\mathbf{r =\dfrac{kq^2}{ 0.01 \Bigg [ m_{o \pi}c^2 \Big [\dfrac{1}{\sqrt{1 - \dfrac{v_{\pi}^2}{c^2} }} \Big ] \Bigg] }}[/tex]
where:
r = distancek = Columb's constantq = charge on a protonm_o = rest mass of each pion in the previous questionc = velocity of light[tex]\mathbf{v_\pi}[/tex] = calculated velocity of proton in the previous questionReplacing their values in the above equation, the distance (r) between the pions is calculated as:
[tex]\mathbf{r =\dfrac{(9\times 10^9 \ N.m^2/C^2) (1.6022 \times 10^{-19} \ C)^2}{ 0.01 \Bigg [ (2.5 \times 10^{-28\ kg } )\times (3\times 10^8 \ m/s)^2 \Big [\dfrac{1}{\sqrt{1 - \dfrac{(2.97 \times 10^8 \ m/s)^2}{(3 \times 10^8 \ m/s)^2} }} \Big ] \Bigg] }}[/tex]
distance (r) = 1.45 × 10⁻¹⁶ m
Therefore, we can conclude that the distance r between the pions when the criteria are satisfied is 1.45 × 10⁻¹⁶ m
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Please help me as quick as possible!!!!!!! Please, please please!!!!!!
Answer:
23
Explanation:
3x-4
An above ground swimming pool of 30 ft diameter and 5 ft depth is to be filled from a garden hose (smooth interior) of length 100 ft and diameter 5/8 inch. If the pressure at the faucet to which the hose is attached remains at 55 psi, how long will it take to fill the pool
This question involves the concepts of dynamic pressure, volume flow rate, and flow speed.
It will take "5.1 hours" to fill the pool.
First, we will use the formula for the dynamic pressure to find out the flow speed of water:
[tex]P=\frac{1}{2}\rho v^2\\\\v=\sqrt{\frac{2P}{\rho}}[/tex]
where,
v = flow speed = ?
P = Dynamic Pressure = 55 psi[tex](\frac{6894.76\ Pa}{1\ psi})[/tex] = 379212 Pa
[tex]\rho[/tex] = density of water = 1000 kg/m³
Therefore,
[tex]v=\sqrt{\frac{2(379212\ Pa)}{1000\ kg/m^3}}[/tex]
v = 27.54 m/s
Now, we will use the formula for volume flow rate of water coming from the hose to find out the time taken by the pool to be filled:
[tex]\frac{V}{t} = Av\\\\t =\frac{V}{Av}[/tex]
where,
t = time to fill the pool = ?
A = Area of the mouth of hose = [tex]\frac{\pi (0.015875\ m)^2}{4}[/tex] = 1.98 x 10⁻⁴ m²
V = Volume of the pool = (Area of pool)(depth of pool) = A(1.524 m)
V = [tex][\frac{\pi (9.144\ m)^2}{4}][1.524\ m][/tex] = 100.1 m³
Therefore,
[tex]t = \frac{(100.1\ m^3)}{(1.98\ x\ 10^{-4}\ m^2)(27.54\ m/s)}\\\\[/tex]
t = 18353.5 s = 305.9 min = 5.1 hours
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Assume that two cars have the same kinetic energy, but that the red car has twice the speed of the blue car. We then know that the red car has ____ mass as the blue car.
Answer:
equal
Explanation:
Can someone PLEASE help me??
E TRUE OR FALSE: Write the word TRUE if the statement is correct, and FALSE if it is not. (3 points each). Write your answer on a separate sheet of paper. 1. Most EM waves has the same speed. 2. EM waves travel at the speed of 4x108 m/s. 3. Electromagnetic waves are transverse waves consisting of changing electric fields and changing magnetic fields. 4. Electromagnetic waves transfer energy through a vacuum. 5. A wave is a disturbance that transfers energy .what the answer?
Answer:
TRUE
FALSE
TRUE
TRUE
TRUE
TRUE
Explanation:
1. Most EM waves has the same speed. True
2. EM waves travel at the speed of 4x108 m/s. False
3. Electromagnetic waves are transverse waves consisting of changing electric fields and changing magnetic fields. True
4. Electromagnetic waves transfer energy through a vacuum. True
5. A wave is a disturbance that transfers energy. True
What are cyclotrons and how are they used?
How do humans obtain the carbon and energy they use in their bodies?
A. by breathing in carbon dioxide from the atmosphere
B. by consuming plants or other animals
C. by absorbing energy from sunlight
D. by absorbing carbon found in the soil
Answer:
B. . by consuming plants or other animals
Find the time it takes for an object dropped from a building and reaches a final velocity of 20 m/s downward?
I need the formula
Answer:
Explanation:
v = at
t = v/a
t = 20 m/s / 9.8 m/s²
t = 2.0408163...
t = 2.0 s
A. praised
B. scolded
C. rewarded
14. Reicon's parents admonished him for breaking their antique collection,
D. silenced
15. I am an advocate of anti-corruption movement in the country.
D. supporter
C. enemy
DirectioRead the statements below. Using context clues, identify the meaning
A. opponent
B. primer
highlighted words.
16. The hotel abolishes its rice-all-you-can policy to avoid wastage of food.
b. removes
d. proposes
A. continues
17. The country has a very tropical climate where it only has dry and wet
seasons similar to other countries in Southeast Asia
a. humid
b. cold
d. normal
-
c. comfortable
d. collected
a. new
c. outdated
18. The obsolete books and other references in the library resulted to the
removal in the shelves and inventory.
b. old
19. Beverages, such as juices, milk, beers and sodas, have increased in
,
due to low supply and importation issues.
a. drinks b. food
d. pastas
20. The luxurious life of my cousin in an exclusive subdivision in Ta
makes me inspired to dream and work hard for me to escape this unp
d.
a. ordinary b. fantastic
c. uncomfortable
c. bread
Help help me plis po summative test ko po ito plis help me
Answer:
14. scolded
15. supporter
16. i am not sure but I think it is removes
17. comfortable
18. outdated
19. drink
20. it can be fantastic or wealthy
Answer:
14. Reicon's parents admonished him for breaking their antique collection,
scolded15. I am an advocate of anti-corruption movement in the country.
supporter16. The hotel abolishes its rice-all-you-can policy to avoid wastage of food.
it is removes17. The country has a very tropical climate where it only has dry and wet
seasons similar to other countries in Southeast Asia
comfortable18. The obsolete books and other references in the library resulted to the
removal in the shelves and inventory.
outdated19. Beverages, such as juices, milk, beers and sodas, have increased in,due to low supply and importation issues.
drinks20. The luxurious life of my cousin in an exclusive subdivision in Ta makes me inspired to dream and work hard for me to escape this unp.
fantasticHelp pls!
A 3 kg mass is raised a distance of 14 m above the earth by a vertical force of 93 N.
The final kinetic energy of the mass, to 3 significant figures, if it was originally at rest is:
[tex] \large★·.·´¯`·.·★ {Answer}★·.·´¯`·.·★[/tex]
As we know that Kinetic Energy is the Energy that is possessed by a moving object. and if the object is at rest then it doesn't have velocity therefore there is no kinetic Energy.
In the numerical terms we can express it as : -
[tex] \sf0.00 \: \: joules[/tex][tex]꧁ \: \large \frak{Eternal \: Being } \: ꧂[/tex]
Which of the vectors in the graph below is the negative of the vector v
A. a
B. d
C. c
D. b
Answer:
Option c.
Explanation:
An object at rest on a flat, horizontal surface explodes into two fragments, one seven times as massive as the other. The heavier fragment slides 5.60 mm before stopping. How far does the lighter fragment slide
Answer:
M1 + M2 = 0 total momentum before explosion = momentum after explosion where M1 is the lighter fragment
M1 V1 + 7 M1 V2 = 0
V2 = -V1 / 7
The lighter fragment will slide 7 times as far - 39.2 mm because it must have 7 times as much velocity - assuming the distance slid is proportional to the original velocity
Which item is not a solid-state component?
an integrated circuit
a vacuum tube
a diode
a transistor
Answer:
a vacuum tube is NOT a solid state component
An object is dropped from a vertical height of 1.89 m above the balcony level. What is the object’s speed when it is 2.20 m below the balcony level if 10.0% energy is lost due to the air resistance? Does it matter when to apply 10% loss before V calculations or after? [8.49m/s] [yes it does, 0.9Energy result in √0.9Velocity]
Answer:
The 10% must come off the energy, not the velocity
Explanation:
Change in height h = 1.89 + 2.20 = 4.09 m
Potential energy = mgh = m(9.81)(4.09) = 40.1m J
Friction losses 40.1m(0.10) = 4.01m J
Kinetic energy at end 40.1m - 4.01m = 36.1m J
KE = ½mv²
v = √(2KE/m)
v = √(2(36.1m)/m = √72.2
v = 8.4983...
v = 8.50 m/s
A circular coil having 60 turns has a radius of 75 mm. What current must exist in the coil
to produce a magnetic field of 300 μT at the center of the coil?
Answer:
Explanation:
Step 1 of 4
CONCEPT:
The mathematical expression for magnetic field B at center of a coil:
Here, is the current in the coil, N is the number of turns of the coil, is the permeability of the free space and is radius of the coil.
Rearrange above equation for current in the coil.
What is the formula of [tex]\underline{force}[/tex]in physics?
The formula of force is F = ma.
Force: This can be defined as the product of mass and acceleration. The S.I unit of force is Newton (N). Force is a vector quantity
Types of force
Friction forcePushPullUpthrustTensional force.
⇒ The formula of force is
F = ma................ Equation 1
⇒ Where:
F = forcem = mass of the bodya = accelerationHence, the formula of force is F = ma.
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Before looking at the formula, Lets understand what is force?
Force:- Force can be defined as the cause of motion of an object. Force can change the shape, direction and velocity of an object.It's SI unit is NewtonThe formula used to find force is:
[tex] \sf \nrightarrow \: F=m×a[/tex]
Where,
F is forceM is mass of the bodyA is accelerationEquation in words:- Force applied on an object is directly proportional or equal to the product of the mass of object and the acceleration of object.
2 W' is the symbol of a) antimony b) gold c) polonium d) tungsten
Answer:
D. Tungsten
Explanation:
W - Wolfram
What is the average SPEED/VELOCITY of a car that traveled 1 complete lap around an oval track that’s 5000m long in 1000s
Answer:
5 m/s
Explanation:
5000/1000=5 m/s
:))
What is the angle of incidence when incident ray is reflected backwards along the same path
Answer:
The angle of incidence = The angle of reflection
Explanation:
For instance, the formula is <i = <r which means if the surface is smooth then the reflacted anglw will be equal according to the normal (dotted 90°) line.
Upon being reflected backwards the angle of incidence is simply the same, except from the other side
What conclusion can you draw from the information shown in this figure?
The speed of sound varies with the material in which the waves travel.
Sound waves can move more quickly through liquids than through solids.
Sound intensity is greater in water than in air.
The frequency of sound increases with wave speed.
Answer:
The speed of sound varies with the material in which the waves travel.
Explanation:
knowledge and research
It can be concluded as per the given table that the speed of sound varies with the material in which the waves travel. The correct option is A.
What is speed?Speed is the pace at which an object's position changes in any direction. The distance travelled in relation to the time it took to travel that distance is how speed is defined. Since speed simply has a direction and no magnitude, it is a scalar quantity.
It has a dimension of time-distance. As a result, the fundamental unit of time and the basic unit of distance are combined to form the SI unit of speed. Thus, the metre per second (m/s) is the SI unit of speed.
According to the given table, it can be inferred that the material in which the waves travel affects the speed of sound.
Thus, the correct option is A.
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Just need the answer
Answer:
1. 1, 2, 4 all show some form of refraction as the bending of a light ray when passing from one media to another.
Explanation:
Number 4 is the most accurate as it also shows some light being reflected and the bending of the refracted light ray in the correct direction for going from a medium of low refractive index (air) into a higher refractive index material (crown glass)