An ice skater spins at 2.5 rev/s when his arms are extended. He draws his arms in and spins at 10.0 rev/s. By what factor does his moment of inertia change in the process?
Answer:
The moment of inertia decreased by a factor of 4
Explanation:
Given;
initial angular velocity of the ice skater, ω₁ = 2.5 rev/s
final angular velocity of the ice skater, ω₂ = 10.0 rev/s
During this process we assume that angular momentum is conserved;
I₁ω₁ = I₂ω₂
Where;
I₁ is the initial moment of inertia
I₂ is the final moment of inertia
[tex]I_2 = \frac{I_1 \omega_1}{\omega_2} = \frac{I_1*2.5}{10} \\\\I_2 = 0.25I_1 = \frac{1}{4}I_1[/tex]
Therefore, the moment of inertia decreased by a factor of 4
Examples of pure substances are elements and _________.
A. Mixtures
B. Compounds
Answer:
b
Explanation:
Answer:
b
Explanation:
trust
A skier reaches the end of a 0.9 km track in 1.5 hours, at what speed does it travel?
(Please help,I need the answer as soon as possible)
Speed = Distance/Time
S = D/T
D = 0.9Km, T = 1.5hours,
S = 0.9/1.5
S = 0.6 m/s
hope it helps!
Answer: Speed =
distance = 0.9 * 1000 = 900 metres, because speed is measured in m/s so the km has to be converted to m
time = 1.5 * 60 = 90 seconds , because speed is measured in m/s so the time in minutes(m) has to be converted to seconds(s)
Speed =
= 10m/s
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Explanation: I don't know what this is but this is what I found and I hope it's helpful
A car takes 15 minutes to travel along a road that is 20 km long.
What is the average speed of the car?
A. 75 km/h B. 5.0 km/h C. 80 km/h D. 300 km/h
Answer:
C
Explanation:
15. 20
x4. x4
60. 80
80km/h
Answer:
80km/h
Explanation:
solution
given
d=20km
t=15min/60min=0.25h
s=?
s=d/t
s=20km/0.25h
s=80km/h
Choose the best definition for velocity
1. How fast something is going
2. Speed in a certain direction
3. Which direction something is going
4. Something speeding up
At a grocery store, 20 fl oz of brand A vitamin
water is sold for $0.95. What is the unit price of
the vitamin water per ounce, to the nearest cents?
Answer:
0.05 cents per fl oz
Explanation:
0.95 divided by 20
0.0475 to the nearest cent 0.05
Heat pumps move heat from __________ to __________ areas & REQUIRES energy. *
A. cold, hot
B. hot, cold
What is the electrical power when the current is 20 amps and the voltage is 15 volts? *
A. 35 watts
B. 1.33 watts
C. 300 watts
Work is a transfer of matter. *
A. True
B. False
A pendulum is swinging back and forth with a period of 2.0 seconds here on Earth. This pendulum is then brought to the Moon, where the acceleration due to gravity is much smaller. What will happen to the period of the pendulum, assuming everything else about it (mass, length, initial swing height, etc) remains exactly the same
Answer: The period will be larger, with T = 4.92 seconds
Explanation:
The period of a pendulum can be obtained by the equation
T = 2*pi*√(L/g)
Where pi = 3.14, L = lenght of the pendulum and g = gravity acceleration.
You can see that the gravitational acceleration is on the denominator, this means that if we decrease the value of g, then the value of T will increase.
In Earth we have that:
2s = 2*3.14*√(L/9.8m/s^2)
L = (1/3.14)^2*9.8 m = 1m
In the moon we have g = 1.62 m/s^2
then the period in the moon is:
T = 2*3.14√(1/1.62) = 4.92s
mix 4 L of 30°C water is 6 L of 40°C water and you’ll have water at what temperature?
Answer:
dont know
Explanation:
need points
Select the correct answer.
The motion of a car on a position-time graph is represented with a horizontal line. What does this indicate about the car's motion?
А.
It's not moving
B.
It's moving at a constant speed.
It's moving at a constant velocity
D. It's speeding up.
Answer:
a
Explanation:
Answer:
its a because its the only thing not moving
Explanation:
An air-track glider attached to a spring oscillates between the 10.0 cm mark and the 61.0 cm mark on the track. The glider completes 11.0 oscillations in 31.0 s
Answer:
T = 2.82 seconds.
The frequency [tex]\mathbf{f = 0.36 \ Hz}[/tex]
Amplitude A = 25.5 cm
The maximum speed of the glider is [tex]\mathbf{v = 56.87 \ rad/s}[/tex]
Explanation:
Given that:
the time taken for 11 oscillations is 31 seconds ;
SO, the time taken for one oscillation is :
[tex]T = \frac{31}{11}[/tex]
T = 2.82 seconds.
The formula for calculating frequency can be expressed as :
[tex]f = \frac{1}{T}[/tex]
[tex]f = \frac{1}{2.82}[/tex]
[tex]\mathbf{f = 0.36 \ Hz}[/tex]
The amplitude is determined by using the formula:
[tex]A = \frac{d}{2}[/tex]
The limits that the spring makes the oscillations are from 10 cm to 61 cm.
The distance of the glider is, d = (61 - 10 )cm = 51 cm
Replacing 51 for d in the above equation
[tex]A = \frac{51}{2}[/tex]
A = 25.5 cm
The maximum speed of the glider is:
[tex]v = A \omega[/tex]
where ;
[tex]\omega = \frac{2 \pi}{T}[/tex]
[tex]\omega = \frac{2 \pi}{2.82}[/tex]
[tex]\omega = 2.23 \ rad/s[/tex]
[tex]v = A \omega[/tex]
[tex]v = 25.5 *2.23[/tex]
[tex]\mathbf{v = 56.87 \ rad/s}[/tex]
The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.
Answer:
Pmax = 67.5 KN
Explanation:
We need to calculate the maximum allowable value of P for both aluminum and steel bars.
FOR STEEL BARS:
Since,
(σallow)st = (Pmax)st/A
where,
(σallow)st = maximum allowable stress of steel bar = 200 MPa = 2 x 10⁸ Pa
A = Cross-sectional area of steel bar = 450 mm² = 0.45 x 10⁻³ m²
(Pmax)st = Maximum allowable force for steel bar = ?
Therefore,
2 x 10⁸ Pa = (Pmax)st/0.45 x 10⁻³ m²
(Pmax)st = (2 x 10⁸ Pa)(0.45 x 10⁻³ m²)
(Pmax)st = 9 x 10⁴ N = 90 KN
FOR Aluminum BARS:
Since,
(σallow)al = (Pmax)al/A
where,
(σallow)al = maximum allowable stress of Al bar = 150 MPa = 1.5 x 10⁸ Pa
A = Cross-sectional area of Aluminum bar = 450 mm² = 0.45 x 10⁻³ m²
(Pmax)al = Maximum allowable force for Aluminum bar = ?
Therefore,
1.5 x 10⁸ Pa = (Pmax)al/0.45 x 10⁻³ m²
(Pmax)al = (1.5 x 10⁸ Pa)(0.45 x 10⁻³ m²)
(Pmax)al = 6.75 x 10⁴ N = 67.5 KN
Since,
(Pmax)al < (Pmax)st
Therefore,
The maximum allowable force will be:
Pmax = (Pmax)al
Pmax = 67.5 KN
When a feather and coin are dropped towards the surface of the earth , do they reach ground together
Answer:
The coin will reach the ground first.
Explanation:
Because feather's mass is very low in comparison to a coin and due to air present in earth's atmosphere it will come down slowly.
hope it helps!
Answer:
The coin
Explanation:
Because the coin is heavier than the feather
What causes atoms to bond together
?!?
Answer:
electrostatic attraction
Explanation:
Atoms form chemical bonds with other atoms when there's an electrostatic attraction between them. This attraction results from the properties and characteristics of the atoms' outermost electrons, which are known as valence electrons.
Se tienen 2 vectores cuyos módulos están en la misma razón que 5 y 2. Si cuando forman 53º su resultante mide 3√29u, ¿Cuánto mide el mayor vector?
Answer:
|v2| = 3.27
Explanation:
You have two vector v1 and v2. The relation between the magnitudes of both vectors is given by:
[tex]\frac{|v_1|}{|v_2|}=\frac{5}{2}[/tex]
Furthermore, the projection (the dot product) of one vector on the other one is given by the following formula:
[tex]v_1 \cdot v_2 = |v_1||v_2|cos\theta[/tex]
The dot product between v1 and v2 is 3√29. If you multiply the right hand side of the last equation by |v2|/|v2| you obtain:
[tex]3\sqrt{29}=\frac{|v_1|}{|v_2|}|v_2|^2cos(53\°)[/tex]
you do |v2| the subject of the formula:
[tex]|v_2|=\sqrt{\frac{|v_2|}{|v_1|}\frac{3\sqrt{29}}{cos53\°}}\\\\|v_2|=\sqrt{\frac{2}{5}\frac{3\sqrt{29}}{cos53\°}}=3.27[/tex]
The passage helps the reader to draw conclusions about which character's perspective? ºAlec ºAlice ºAlec's father ºAlec's mother
Answer:
I think it might be A: Alec but tell me if I'm wrong
Explanation:
Answer:
a
Explanation:
i did it on e d g e n u i t y
2. A new racecar track is being created, and the owners want the cars to complete 10
miles in 7 laps. What does the diameter of the track have to be to meet their
requirements?
Answer:
0.45 miles
Explanation:
since, car will be running on the edge of track, distance covered in one lap by car will be equal to circumference of track.\
we will use value of pi as 22/7
Circumference for any circular shape is given by [tex]\piD[/tex][tex]\pi D[/tex]
Hence, in one lap [tex]\pi D[/tex] distance will be covered
in 7 laps [tex]7 \pi D[/tex] distance will be covered.
but is given that 7 laps should be equal to 10 miles
so 10 miles will be equal to [tex]7\pi D[/tex]
[tex]7\pi D= 10 \ miles\\=> 7*(22/7)* D= 10 \ miles\\=> 22D = 10 \ miles\\=> D = 10/22 \ miles\\=> D = 0.45 \ miles[/tex]
Thus, diameter of track will be 0.45 miles to meet the requirement.
What has an ionised atom lost or gained?
Protons
Gamma Rays
Electrons
Neutrons
Answer:
Electrons
Explanation:
Ionised atoms loose and gain electrons.
hope it helps!
Which of the following are two factors that determine speed?
a. acceleration and time
b. distance and time
c. velocity and time
d. motion and time
Answer:
B) Distance and Time
Explanation:
Equation for speed: S = D / T
Speed equals the distance you traveled divided by the amount of time it took to get to that destination.
The two factors which are required to determine the speed of a object are distance traveled by it and time taken by it.
What is speed?The speed is the rate at which the total distance by a object is traveled in the time taken.
Speed of a object can be given as,
[tex]s=\dfrac{d}{t}[/tex]
Here, (d) is the distance traveled by the object and (t) is time taken but the object to cover that distance.
As the unit of the distance is measured in the meter and the time measure in the second. Thus the speed of a object is measured in the meter per second.
In the vehicles the speed of vehicle is also measured in the kilometre per hour or miles per hour.
Hence, the two factors which are required to determine the speed of a object are distance traveled by it and time taken by it.
Thus the option B is the correct option.
Learn more about the speed here;
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explain nuclear fusion briefly
Answer:
Nuclear fusion is the process in which two atomic nuclei are fused together into a larger single nucleus, releasing energy in the process. ... In proton-proton fusion, four hydrogen atoms are fused into a single helium-4 atom, releasing a lot of energy in the process.
Explanation:
Which energy output objects work with the turbine?
Which structure connects muscles to bone?
Answer: tendons connect muscles to bones
Explanation:
30
. Which of the following represents the
statement "The difference of two square
numbers is positive
Answer:
In mathematics, the difference of two squares is a squared (multiplied by itself) number subtracted from another squared number. Every difference of squares may be factored according to the identity. in elementary algebra.
Explanation:
What is motion ,terms used to measure motion ,examples etc
Answer:
A physic term
Explanation:
Answer:
Cambio de lugar o de posición de un cuerpo en el espacio.
Explanation:
Jenny and Fred both play a long note on their trombones. A stationary observer hears the sound increasing and decreasing repeatedly in loudness. Which of these must be true?
A.The sound waves from the two trombones have slightly different frequencies.
B. The sound waves from the two trombones have the same frequency.
C. The sound waves from the two trombones have slightly different amplitudes.
D. The sound waves from the two trombones have the same wavelength.
E. The sound waves from the two trombones have slightly different velocities.
Answer:
A.The sound waves from the two trombones have slightly different frequencies.
Explanation:
This is because, a difference in frequency of waves from two different sources would result in either constructive or destructive interference of the waves. Thereby, causing the observer to hear the sound increasing or decreasing.
Answer:
A.The sound waves from the two trombones have slightly different frequencies.
Which happens during the day at the beach?
A. The water is warmer than the land, and air sinks over the water
B. The water is cooler than the land, and air sinks over the water
C. The water is warmer than the land, and air rises over the water
D. The water is cooler than the land, and air rises over the water
Answer:
c
Explanation:
not sure i think heating beach
Un semáforo de 80N cuelga del punto medio de un cable de 30m tendido entre 2 postes. Halle la tensión en cada segmento del cable si éste tiene un pandeo que lo hace descender una distancia vertical de 1m
Answer:
T1 = T2 = 602.33 N
Explanation:
I attached an image of the forces diagram below.
The x component of the forces for this cases is:
[tex]\Sigma F_x=T_1cos\theta-T_2cos\theta=0\\\\T_1cos\theta=T_2cos\theta\\\\T_1=T_2[/tex]
And the y components:
[tex]\Sigma F_y=T_1sin\theta+T_2sin\theta-W=0\\\\T_1=T_2=T\\\\\Sigma F_y=2Tsin\theta=W\\\\T=\frac{W}{2sin\theta}[/tex]
The angle is calculated by using the information about the length of the cable and the vertical distance of the traffic light:
[tex]\theta=tan^{-1}(\frac{1}{15})=3.81\°[/tex]
Thus, you obtain:
[tex]T=\frac{80N}{2(sin3.81\°)}=601.33N[/tex]
hence, the tension in both segments of the cable is 602.33 N
This diagram shows a baseball’s motion. Which statement is best supported by the diagram?
a
Maximum Gravitational potential energy is at point R.
b
Kinetic energy becomes potential energy between points P and Q.
c
Kinetic energy becomes potential energy between points R and S.
d
Maximum kinetic energy is at point R.
Answer:
A
Explanation:
maximum gravitional potential energy is at point R
A 1200 kg car accelerates from 13m/s to 17m/s. find the change in momentum of the car?
Answer:
4800
Explanation:
The change in velocity of the car is 17-13=4m/s. Since the change in momentum is the mass multiplied by the change in velocity, the answer is 4*1200=4800. Hope this helps!
Given:
Mass,
m = 1200 kgChange in velocity,
Δv = 17-13= 4 m/s
Now,
The change in momentum is:
= [tex]Mass\times Change \ in \ velocity[/tex]
= [tex]1200\times 4[/tex]
= [tex]4800[/tex]
Thus the above answer is correct.
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can someone tell me the answer for both of these pleaseeee i need it asap!!! i will give brainlist!!
Answer:
1/ decreases
2/ yes;
In general there is no relationship, and any combinations of frequencies and amplitudes are allowed.
Explanation:
Explanation for 1/ - please see the picture attached below
