Answer:
0.25 Hz
4 s
Explanation:
Speed = wavelength × frequency
7 m/s = 28 m × f
f = 0.25 Hz
Frequency = 1 / period
0.25 Hz = 1 / T
T = 4 s
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
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]
In an inelastic collision, which of the following statements is always true?
[A] Kinetic energy is conserved in the collision.
[B] Momentum is conserved in the collision.
[C] After the collision, the objects always merge into one.
[D] The collision takes more that 1 second to complete.
Answer: A
Explanation:
A
. How does the intensity of sunlight received affect Earth’s temperatures?
I’m a freshman, I got a 80% in the first quarter, 85% in the second and 70% in the third. I have a 46% in the fourth and 34 total absences in the class. If I fail, will I fail the class or the entire grade
Answer:
you will pass but if your grade become lower and u get more absences you will fail
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
A charge of 80 coulombs passes through a circuit in 5 seconds. What is the current through the circuit?
Answer:
I = 16amp
Explanation:
Charge coulomb ( Q ) = It
Where I =current in ampere
t = time = 5 seconds
80 = I × 5
I = 80/5
I = 16amp
The current through the circuit will be I = 16amp
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]
Which phrases describe all the outer planets’ motion? Select two options.
no rotation
fast rotation
slow revolution
opposite revolution
north to south rotation
Answer:
Fast rotation
Slow revolution
Explanation:
Solar system has 8 planets. 4 inner rocky planets - Mercury, Venus, Earth and Mars and 4 outer gaseous planets - Jupiter, Saturn, Uranus and Neptune. The outer planets have few common features.
They are gaseous. There period of revolution is larger than the inner planets which means that they have slow revolution about the Sun. One day on the outer planets is smaller than the inner planets which means they have fast rotation.
For example, Jupiter has revolves around sun in 11.86 Earth years and rotates about axis in 9.8 Earth hours. Uranus revolves around sun in 84 Earth years and rotates on its axis 17.9 Earth hours.
Answer:
Fast rotation
Slow revolution
Explanation:
did the test
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!
8000 kg engine pulls a train of 5 wagons, each of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate the net accelerating force
Answer:
The net force of engine on total mass of train is 35000 N
The net acceleration is 1.944 m/s²
Explanation:
Here we have;
Mass of each wagon of train = 2000 kg
Number of wagons = 5
Total mass of wagons = 5 × 2000 = 10000 kg
Mass of engine = 8000 kg
Total mass, m of train (engine plus wagons) = 10000 + 8000 = 18000 kg
Force exerted by train = 40000 N
Friction force due to the railway track = 5000 N
Net force, F of engine on total mass of train = 40000 - 5000 = 35000 N
Formula for force, F = Mass, m × Acceleration, a
35, 000 = 18,000 × a
a = 35,000/18,000 = 35/18 m/s²
[tex]a = 1\tfrac{17}{18} \ m/s^2[/tex]
The net acceleration = 1.944 m/s².
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 man is trying to move a piano by himself, but it will not move, what force must they overcome to start the piano moving?
Answer:
The friction of the piano and the weight
Explanation:
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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When you have two materials with the same index of refraction, it means that
Answer:
When you have two materials with the same index of refraction, it means that if they are touched by a ray of light it won't have a chance, and its form would prevail.
Explanation:
The reason behind this is that in the first place. When light passes through an object of certain refraction it is modified from its natural state, allowing it to change in color to the human eye or many other effects in other perceptive elements. However, when the same light passes through two objects with the same refraction due to their physical characteristics, it doesn't change because once it comes out of the first one it will suffer the same effect from the last one. For it to change the refraction would have to be higher or lower. Then it would be modified. The reason is because the dimensions are not modified. Because at some point the ray of light has to come out of the first one to enter the second one.
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:
What type of phase change occurs when water vapor in the atmosphere changes to liquid water in clouds?
Answer:
condensation, the process of changing from a gas to a liquid
Rafael swings a baseball bat with a force of 25 N. The baseball bat exerts a force of 5 N on the baseball. What is the mechanical advantage of the baseball bat? The mechanical advantage of the baseball bat is
Answer:
0.2
Explanation:
Mechanical Advantage is defined as the ratio of force output with respect to the force input. Thus,
MA = output / input
MA = 5 / 25
MA = 1/5
MA = 0.2
Since this value is less then one. Even though it's tagged a mechanical advantage, in reality it would be mechanical disadvantage.
Therefore, we can say that the mechanical advantage of the baseball bat is 0.2
Answer:
0.2
Explanation:
A paint brush is dropped from the top of a tall ladder and free falls to the ground. What changes, if any, would be observed of the velocity and the acceleration of the brush as it falls? Pick the two answers. The velocity increases. The velocity decreases. The velocity remains a constant value. The acceleration increases. The acceleration decreases. The acceleration remains a constant value.
Answer:
Explanation:
As the paint brush is dropped from the top of a tall ladder it started free falling
i.e. velocity of brush increases as it falls down due to the acceleration provided by gravity.
We know acceleration due to gravity is the attraction experienced by the object due to earth attraction
Value of acceleration due to gravity is constant i.e. [tex]9.8\ m/s^2[/tex]
Therefore the correct choice is
velocity is increasing and acceleration is constant
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:
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
Which of the following is a conversion from light energy to chemical energy?
a. turning on a stove to heat dinner
b. growing an apple tree
c. turning on a lamp
d. Turning on a blender
Answer:
A
Explanation:
turning on a stove to heat dinner because it undergoes a chemical reaction to transform into other substance
Growing up a tree is a conversion from light energy to chemical energy.
What is law of energy conservation?Energy can neither be created nor be destroyed , it gets only transferred from one form to another.
What is photosynthesis?The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.In simple words by the process of photosynthesis a tree makes food for itself.What happens when a tree grows?Tree makes food by absorbing the sunlight.The energy of the sunlight is used in making of ATPs in trees.ATP ( Adenosine triphosphate ) is used in various operations in trees.So, the sunlight is light energy which get converted into ATPs , which is chemical energy.
Thus, Growing up a tree is a conversion from light energy to chemical energy.
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Gold, quartz, and talc are minerals. Copper and iron are types of ore. What is the difference between minerals and ores?
A mineral is a non-living, solid substance that can be extracted from the ground. Ore is a type of mineral made up of metals.
An ore is non-living and solid with little value unless it occurs in large amounts, in which case it is a mineral.
O A mineral is a valuable form of ore that can be extracted from the ground
O A mineral is a non-living, solid substance made of elements. Ore is a large deposit of one or more valuable minerals in the ground.
Answer:
A mineral is a valuable form of ore that can be extracted from the ground
Explanation:
Gold, quartz and talc are minerals because they are found in the earth in a valuable form of ore while ores are rocks that contain valuable concentrations of minerals.that can be mined.
An ORE in general term can be said to be a mineral deposit that contains enough Minerals that can be mined in commercial quantities while Minerals are valuable components of an Ore that can be mined ( naturally occurring ) in an ORE.
What energy transformations take place in Joule's system?
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:
A circuit has a current of 3 A. How many coulombs of charge will pass by a point in the circuit in 2 seconds?
- 6C
- 5C
- 3/2 C
- 2/3 C
One of these are the answer..
6C
Explanation:
The quantity of charge, Q, passing through an electric circuit is dependent on the electric current, I, and the time taken, t, for the current to flow. It is given mathematically as follows
Q = I x t ------------------------------(i)
Where;
I is measured in Amperes(A)
t is measured in seconds (s)
Q is measure in coulombs (C)
From the question,
I = 3A
t = 2s
Substitute these values into equation (i) as follows;
Q = 3 x 2
Q = 6C
Therefore, the number of coulombs of charge that will pass is 6C
On a sky coaster (human pendulum) that reaches 20 meters from it's equilibrium position, a man of 70 kg is able to reach a maximum speed of
Answer:
Explanation:
Using the principle of conservation of energy, the potential energy is converted to kinetic energy, assuming any losses.
Kinetic energy is given by ½mv²
Potential energy is given by mgh
Where m is the mass, v is the velocity, g is acceleration due to gravity and h is the height.
Equating kinetic energy to be equal to potential energy then
½mv²=mgh
V
Making v the subject of the formula
v=√(2gh)
Substituting 9.81 m/s² for g and 20 m for h then
v=√(2*9.81*20)=19.799 m/s
Rounding off, v is approximately 20 m/s
Answer:
19.8 m/s
Explanation:
During the motion of a pemdulum bob, it casually converts kinetic energy to potential energy and vice versa.
A pendulum bob reaches its maximum speed at a position closest to its equilibrium position and has its lowest when it is farthest from the equilibrium position.
The maximum speed of a pendulum bob based on the mass involved and the maximum displacement from the equilibrium position is obtained from
Maximum kinetic energy = Maximum potential energy
Maximum potential energy occurs at the farthest point from equilibrium, that is,
P.E(max) = mgh
Maximum kinetic energy = ½mv²
½mv² = mgh
v = √2gh
g = acceleration due to gravity = 9.8 m/s²
h = farthest height from equilibrium position = 20 m
v = √(2×9.8×20) = 19.8 m/s
Hope this Helps!!!
What is the formula for velocity???
Explanation:
divide the distance by the time it takes to travel that same distance, then add your direction to it.
Or change in displacement divided by change in time.
En la etiqueta de un bote de fabada de 350 g, leemos que su aporte energético es de 1630 kj por cada 100 g de producto a) La cantidad de fabada que tiene que comer un hombre si su necesidad energética diaria es 2500 kj para sobrevivir b) El aporte calórico del bote de fabada en calorías
Answer:
(a) 153.37 g
(b) 5705 kJ
Explanation:
(a) To find the amount of bean needed by a man you first calculate the equivalence in beans to 2500kJ
[tex]2500kJ*\frac{100g}{1630kJ}=153.37\ g[/tex]
Thus, 153.37 g has the energy needed by a man that needs 200kJ per day.
(b) The amount of energy per pot of bean is given by:
[tex]E=350g*\frac{1630kJ}{100g}\\\\E=5705\ kJ[/tex]
Thus, the energy is 5705kJ
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
