Answer:
v = 37.59 km/h
Explanation:
The question says, "how fast in km / h did usain bolt run at the berlin world championship in 2009 to break the world record for the 100m sprint in 9.58".
Distance, d = 100 m = 0.1 km
Time, t = 9.58 s = 0.00266 h
We need to find the speed of the Usain Bolt. We know that,
Speed = distance/time
So,
[tex]v=\dfrac{0.1}{0.00266}\\\\v=37.59\ km/h[/tex]
So, the required speed is equal to 37.59 km/h.
can someone answer pls??
Answer:
2. the volume of the square are the same
Answer:
the volume of the squares are the same
Explanation:
A certain capacitor, in series with a resistor, is being charged. At the end of 25 ms its charge is half the final value. The time constant for the process is about:
Answer:
τ = 36 10⁻³ s
Explanation:
The charge of a circuit Rc is given by the expression
q = q₀ (1 - [tex]e^{-t/ \tau }[/tex])
q / q₀ = 1 - e^{-t/ \tau }
in this exercise they indicate that
q / q₀ = ½
for a time t = 25 10⁻³ s
we substitute
½ = 1 - [tex]e^{- 25 \ 10^{-3} / \tau}[/tex]
e^{- 25 \ 10^{-3} / \tau} = 1 -½
- 25 10⁻³ /τ = ln 0.5
-25 10⁻³ / ln 0.5 = τ
τ = 36 10⁻³ s
Tính nhiệt lượng cần cung cấp để đun nóng 5kg nước từ nhiệt độ 25 độ C lên 100 độ C. Biết nhiệt dung riêng của nước là 4,18.10^3 J/kg.K
Answer:
Q = 7837500 Joules.
Explanation:
Cho các dữ liệu sau đây;
Khối lượng = 25 kg
Nhiệt độ ban đầu = 25°C
Nhiệt độ cuối cùng = 100°C
Nhiệt dung riêng = 4,18 * 10³ = 4180 J/kg.K
Để tìm nhiệt lượng cần thiết;
Về mặt toán học, nhiệt dung được cho bởi công thức;
[tex] Q = mcdt[/tex]
Ở đâu;
Q là nhiệt dung hoặc nhiệt lượng. m đại diện cho khối lượng của một vật. c biểu diễn nhiệt dung riêng của nước. dt thể hiện sự thay đổi của nhiệt độ.Chuyển đổi:
Nhiệt độ ban đầu = 25°C đến Kelvin = 273 + 25 = 298 K
Nhiệt độ cuối cùng = 100°C đến Kelvin = 273 + 100 = 373 K
dt = T2 - T1
dt = 373 - 298
dt = 75 Kelvin
Thay các giá trị vào phương trình, ta có;
[tex] Q = 25 *4180*75[/tex]
Q = 7837500 Joules.
Tần số ngưỡng của một kim loại có giá trị X. Nếu tần số của chùm sáng chiếu đến bề mặt katot tăng từ 2X đến 4X thì cường độ dòng quang điện sẽ
Answer:
Năng lượng tăng gấp đôi.
Explanation:
Như chúng ta biết
E = nhf
Năng lượng tỷ lệ thuận với f
Thay đổi về tần số sẽ tương đương với những thay đổi tương tự về Năng lượng
Nếu tần số trở thành hai lần, thì năng lượng sẽ trở thành 2 lần.
a 60 kg runner accelerates during a race at 3m/s2. what force is exerted on the earth with each step
Answer:
180 Newton(N)
Explanation:
force =mass *acceleration
=60 * 3
=180 kgm/s^2
=180 N
HELP PLSSS I HAVE AN EXAM MONDAY AND I THINK THIS IS GONNA BE ON ITTTT
A fish is at the western bank of a river that is 64 m wide and has a current with a velocity of 0.90 m/s [S]. The fish swims directly across the river going due east. The fish can swim at a speed of 0.2 m/s.
a) How long does it take for the fish to get across the river
b) What is the resulting velocity of the fish
c) When the fish arrives on the opposite bank, how far is it from being at the point directly across from where it started?
The answers are here, please show work on how to get these
a) 3.2 x 10^2
b) 0.9 m/s (S 13 E)
c) 2.9 x 10^2
(a) 3.2 x 10²s
(b) 0.9 m/s (S 13 E)
(c) 2.9 x 10²m
Explanation:The sketch illustrating the scenario has been attached to this response.
As shown;
The fish swims due east with a velocity [tex]V_{x}[/tex] = 0.2m/s
The river current has a velocity [tex]V_{y}[/tex] due South = 0.9m/s
The resultant of the velocity is V
The width of the river is x = 64m
(a) To calculate how long it took the fish to get across the river, we know that velocity is the rate of change in distance, therefore we can use the relation;
V = [tex]\frac{d}{t}[/tex] -------------(i)
Where;
V = velocity of the fish = [tex]V_{x}[/tex] = 0.2m/s
d = distance from the start to the end = width of the river = x = 64m
t = time taken to move for that distance
Make t subject of the formula in equation (i);
t = [tex]\frac{d}{V}[/tex]
Substitute the values of d and V into the equation;
t = [tex]\frac{64m}{0.2m/s}[/tex]
t = 320 s
t = 3.20 x 10²s
Therefore, the time taken for the fish to get across the river is 3.20 x 10²s
(b) The resulting vector of the fish is V whose magnitude is the algebraic sum of vectors [tex]V_{x}[/tex] and [tex]V_{y}[/tex], and direction is given by θ. i.e
The magnitude of the resulting vector is;
|V| = [tex]\sqrt{(V_x)^2 + (V_y)^2}[/tex]
|V| = [tex]\sqrt{(0.2)^2 + (0.9)^2}[/tex]
|V| = [tex]\sqrt{(0.04) + (0.81)}[/tex]
|V| = [tex]\sqrt{(0.85)}[/tex]
|V| = 0.92m/s
|V| ≅ 0.9m/s
The direction of the resulting vector θ and is given by;
tan θ = [tex]\frac{V_y}{V_x}[/tex]
tan θ = [tex]\frac{0.9}{0.2}[/tex]
tan θ = 4.5
θ = tan⁻¹ ( 4.5)
θ = 77.47° South of East.
θ ≈ 77.5° South of East.
Subtracting θ = 77.5° from 90° gives its value East of South
i.e
90 - 77.5 = 12.5° East of South
This can also be written as S12.5°E
Approximating to the nearest whole number gives S 13 E
Therefore, the resulting velocity of the fish is 0.9m/s in the direction S13°E
(c) When the fish arrives on the opposite bank, its distance from being at the point directly across from where it started is the product of the velocity of the river current and the time taken by the fish to get across the river. This point is equivalent to k as shown in the diagram.
Therefore;
distance = velocity of river current x time taken
distance = 0.9m/s x 3.20 x 10²s
distance = 2.88 x 10²m
distance ≅ 2.9 x 10²m
Notice that the velocity of the river current is used since that's the velocity of the fish on the y-axis.
Calculate the capacitance of a system that stores 9.4 x 10-10 C of charge at
Q
50.0 V. Use C=
AV
O A. 1.9 x 10-11 F
OB. 4.7 x 10-8 F
O C. 5.3 x 1010 F
O D. 2.1 x 107 F
Answer:
A. [tex]1.88\times 10^{-11}\,F[/tex].
Explanation:
By definition of Electric Capacitance, the capacitance of the system ([tex]C[/tex]), in farads, is described by the following formula:
[tex]C = \frac{q}{V}[/tex] (1)
Where:
[tex]q[/tex] - Electric charge, in coulombs.
[tex]V[/tex] - Voltage, in volts.
If we know that [tex]q = 9.4\times 10^{-10}\,C[/tex] and [tex]V = 50\,V[/tex], then the capacitance of the system is:
[tex]C = \frac{9.4\times 10^{-10}\,C}{50\,V}[/tex]
[tex]C = 1.88\times 10^{-11}\,F[/tex]
The correct answer is A.
what can make an inclined plane more efficient?
Answer:
Efficiency can be increase by using rollers in conjunction with the inclined plane. Wedge. The wedge is an adaptation of the inclined plane. It can be used to raise a heavy load over a short distance or to split a log
What are three methods of water conservation that we can do to protect our aquifers, watersheds, and ground water?
Answer:
• Go Native. Use native plants in your landscape. ...
• Reduce Chemical Use. Use fewer chemicals around your home and yard, and make sure to dispose of them properly - don't dump them on the ground!
• Manage Waste. ...
Explanation:
There are some easy ways to conserve water to help protect our aquifers, watersheds, and ground water. First, we can all conserve water, by not running the water while we brush our teeth and making sure we fix all leaking or dripping faucets. Another was to conserve water is to collect rain water to use to water your plants. Speaking of plants, you can also plant more zeroscape type landscapes that require less water. We can also update our shower heads and toilets to be low-flow and more efficient. Can't afford a new toilet? Simply add a brick to your tank and this will cut down on the water used for every flush.
can someone please please helppp... thank u <3
Answer:
uniformly accelerated motion
#CARRY ON LEARNING
#IM 100% SURE
#MARK ME AS BRAINLIEST
Daniel wants to find out if he can notice the difference in light intensity when he adds some lit candles to a set of 50 lit candles. When he adds 5 candles to the set, he notices the difference in intensity half the time. However, when he adds less than 5 candles to his set, he does not notice any difference in the intensity of light. In this scenario, Daniel's difference threshold for detecting the change in light intensity is ________ lit candles.
Answer:
5
Explanation:
The light intensity may be defined as the strength of the light or the magnitude of its brightness that a source of light can produce.
The light threshold is the minimum intensity of the light that our eye can detect and the ability to adapt to darkness.
In the context, Daniel wishes to find if can notice the difference in the intensity of the light when he add 5 candles to the set of 50 candles.
He noticed that when he added 5 candles, he could notice the difference in the intensity and when he added less than 5 candles to the set of 50 candles he could not detect.
Thus, the difference threshold for Daniel to detect the change in the intensity of the light is 5 candles.
A proton is moving toward a stationary charged particle. Which statement correctly describes an energy change that could occur as the particles get closer?
Answer:
Kinetic energy will be converted into electric potential energy if the stationary particle is positive.
match the given circuit parts to their appropriate functions. write only the letter of the correct answer on your paper
1.source a.an appliance/device that uses electricity
2.switch source like bulbs,computers.
3.wire b.it is a safety device made from materials
4.load that easily melt even before the wires
5.fuse carry too much current.
c.it is where electricity came from like
batteries and generators.
d.it is the pathway of electricity from the
resources to the load .
e.it controls the flow of electricity from the
source. it is used to turn on/off a load.
Answer:
a. Load.
b. Fuse.
c. Source.
d. Wire.
e. Switch.
Explanation:
An electric circuit can be defined as an interconnection of electrical components which creates a path for the flow of electric charge (electrons) due to a driving voltage.
Generally, an electric circuit consists of electrical components such as resistors, capacitors, battery, transistors, switches, inductors, fuse, etc.
Matching the given circuit parts to their appropriate functions, we have;
a. Load: an appliance or device that uses electricity source like bulbs, computers, television, radio, etc.
b. Fuse: it is a safety device made from materials that easily melt even before the wires carry too much current.
c. Source: it is where electricity came from like batteries and generators.
d. Wire: it is the pathway of electricity from the resources (source) to the load.
e. Switch: it controls the flow of electricity from the source. It is typically used to turn ON or turn OFF a load.
What causes the mechanical advantage of the inclined plane to be less than that of the lever?
Answer:
The force of friction that is caused when using an inclined plane causes the mechanical advantage of the inclined plane to be less than that of the lever.
Explanation:
Resolver el siguiente problema usando los pasos de Pólya y la estrategia razón, proporción y porcentajes De los 240 viajeros que ocupan un avión, el 30% son asiáticos, el 15% africanos, el 25% americanos y el resto europeos. a) ¿Cuántos europeos viajan en el avión? b) ¿Cuál es el total de asiáticos y americanos que viajan en el avión? c) ¿Cuál es la razón de viajeros africanos a viajeros americanos?
Answer:
a) 72 europeos viajan en el avión, b) 132 pasajeros viajan en el avión, c) Hay una proporción de 3 africanos a 5 americanos en el avión.
Explanation:
a) Si 30 % son asiáticos, 15 % africanos y 25 % americanos, entonces 30 % son europeos. La cantidad de europeos en el avión es:
[tex]x = 0.3\cdot (240)[/tex]
[tex]x = 72[/tex]
72 europeos viajan en el avión.
b) El total de asiáticos y americanos en el avión se determina mediante la siguiente expresión:
[tex]x = (0.3 + 0.25)\cdot (240)[/tex]
[tex]x = 132[/tex]
132 pasajeros viajan en el avión.
c) En primer lugar, se calculan los números de africanos y americanos en el avión:
Africanos
[tex]x_{1} = 0.15\cdot (240)[/tex]
[tex]x_{1} = 36[/tex]
Americanos
[tex]x_{2} = 0.25\cdot (240)[/tex]
[tex]x_{2} = 60[/tex]
Y la razón de viajeros africanos a viajeros americanos es:
[tex]r = \frac{r_{1}}{r_{2}}[/tex]
[tex]r = \frac{36}{60}[/tex]
[tex]r = \frac{3}{5}[/tex]
Hay una proporción de 3 africanos a 5 americanos en el avión.
Trong hình dưới, dòng điện I = 10 A rất dài, đặt trong không khí. Những điểm có cường độ từ trường H = 8,0 A/m nằm cách dòng điện một khoảng bao nhiêu cm
Answer:
bombeees.p lele
Explanation:
trong bon
A massive truck collides with a less massive car. The force experienced by the truck is ____________ (less than, equal to, greater than) the force experienced by the car. The resulting acceleration of the truck is ____________ (less than, equal to, greater than) the resulting acceleration of the car.
Please answer ASAP
Answer:
equal to; less than
Explanation:
newtons 3rd law says that all forces have equal and opposite reactions so it would be equal to for the first one. but the acceleration depends on the mass of the object and because the truck is more massive, the acceleration would be slower, or less than.
what is current and si unit
Answer:
The SI unit of current is ampere which measures the flow of electric charge across a surface at the rate of one coulomb per second.
what is neant by velocity ratio of machine is 3 and efficency is 60%
Answer:
Velocity ratio of a lever is 3 means distance travelled by effort is 3 times the distance travelled by the load. Efficiency of the pulley is 60%means 40% of the energy is lost in the machine due to the friction
If the radius of the equipotential surface of the point charge is 14.3 m at a potential of 2.20 kV, what will be the magnitude of the point charge that generates the potential?
Answer:
The magnitude of the point charge is 3.496 x 10⁻⁶ C
Explanation:
Given;
radius of the surface, r = 14.3 m
magnitude of the potential, V = 2.2 kV = 2,200 V
The magnitude of the point charge is calculated as follows;
[tex]V = (\frac{1}{4\pi \epsilon _0} )(\frac{Q}{r} )\\\\V = \frac{KQ}{r} \\\\Q = \frac{Vr}{K} \\\\Q = \frac{2,200 \times 14.3}{9\times 10^9} \\\\Q = 3.496 \times 10^{-6} \ C\\\\Q = 3.496 \ \mu C[/tex]
Therefore, the magnitude of the point charge is 3.496 μC
As a train starts from rest then accelerates down the track, coming toward an observer faster and faster, the frequency of the sound waves coming toward the observer will be
Answer:
Increase in frequency constantly
Explanation:
This concept can be explained by Doppler shift as per which any form of disturbance spreads out spherically from its point of origin. If the source of sound wave is stationary and the receiver is also stationary, then the frequency remains the same but if the source is moving, then the disturbance caused is closer on one side and distant on the other side thereby producing shorter wavelength in direction the source is moving and longer wavelength in the opposite direction.
In what direction does the force of friction act?
A. Perpendicular to the surface, pointing up
B. Perpendicular to the surface, pointing down
C. Along the surface, in the direction opposite to the motion
D. Along the surface, in the same direction as the motion
can someone please help me with this question... thank u
Answer:
45 degrees
Explanation:
A projectile, in other words, travels the farthest when it is launched at an angle of 45 degrees.
A small part of a current loop consisting of a very, very large triangular conductor in the x-y plane is shown below, with the current i=39.30 A.
12 10 4 2 1 0 1 2 3 4 5 6 7 8 9 10 11 12 x (cm)
Calculate the magnitude of the B-field at point 'p'.
Answer: hello your question is poorly written attached below is the well written question
answer: 4.9 * 10^-5 T
Explanation:
Current ( i ) = 39.30 A
Determine the magnitude of the B-field at Point P
Mag of B-field at Point P = μo*I / 2π*r --- ( 1 )
where : I = 39.30 , μo = 4π * 10^-7 , r = 8*10^(-2)
Input values into equation 1
( 10^-7 * 39.30 ) / ( 8*10^-2 )
∴ Mag of B-field = 4.9 * 10^-5 T
state the mode by which heat travels from the cube to the balloons
Answer:
The face of the cube towards A. is bright and shiny and the face towards B is dull black. State with reason the adjustments that should be made on the distances X1 and X2 so that the rate of change of temperature in both balloons is the same.
Explanation:
Convection is the mechanism by which heat is transferred from the cube to the balloon. Convection is the movement of currents inside a liquid or gas that transfers heat energy.
What is Convection?Convection is a method of heat transfer in which a fluid or gas, such as air or water, is moved. A hotter liquid or gas loses density and rises, while a colder, denser liquid or gas replaces it by sinking. Convection is the term used to describe the movement of gases or liquids due to temperature differences.
When the cube is heated, the air around it becomes less dense and rises; On the contrary, the cold air from all around fills the space. As a result, heat energy is transferred from the cube to the balloons via convection currents.
Therefore, Convection is the mechanism by which heat is transferred from the cube to the balloon. Convection is the movement of currents inside a liquid or gas that transfers heat energy.
Learn more about Convection, here:
https://brainly.com/question/4138428
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A spring stretches from 10cm to 22cm when a force of 4n is applied, if it obeys Hooke’s law,its total length in cm when a force of 6N is applied is?
Answer:
Explanation:
Hooke's Law is a linear representation that, in equation form, looks like this:
F = -kΔx where F is force, k is the spring constant, and Δx is the displacement of the spring when a Force is applied to it in the form of a mass hanging on the end of it. We need to use the equation to solve for the spring constant, k. Doing this by filling in the values we were given:
4 = -k(-12) the 12 is negative because the mass hangs below the point of equilibrium. This gives us that
k = 1/3. Now we'll use that in the next equation where we need to solve for displacement:
6 = -1/3(Δx) and
Δx = -18 cm
What is Newton’s third law?
Answer:
For every action, there is an equal and opposite reaction
Explanation:
Newton's Third Law of Motion states "To every action, there is an equal and opposite reaction; action and reaction forces act on different bodies".
How efficient is a pulley system if an operator has to pull 2.5m of rope to lift a 250 N pail of water a distance of 4.5 m?
Answer:
the pulley system is very efficient
Explanation:
Given;
load, L = 250 N
distance moved by the load, a = 4.5 m
distance moved by the effort, e = 2.5 m
let the force or effort applied = F
Apply the principle of conservation of energy;
F x e = L x a
F = (L x a) / e
F = (250 x 4.5) / 2.5
F = 450 N
The efficient of the pulley system;
E = Output force / Input force
E = (450 x 2.5) / (250 x 4.5)
E = 1 = 100%
Therefore, the pulley system is very efficient
4) Describa una situación en la cual un cuerpo se encuentre en reposo para un observador, y en movimiento para otro.
Answer:
Rest and motion are the relative terms.
Explanation:
When the position of the object does not change with respect to time, the object is said to be at rest.
When the position of the object changes with respect to time, the object said to be in motion.
let there is a tree, the tree is at rest with respect to the person which is standing near by the tree.
But when the person is in outer space and able to see the tree, the tree is in motion as the earth is in motion.
A person sitting in the train which is moving is at rest when observed by the other person sitting in the train but he is in motion with respect to a person which is standing on the platform.
which of the following is not made up of atoms answers choices A heat b tree c balloon
Answer:
the answer is tree
Explanation:
because tree is made up of woodly barks and not atoms so we can say that tree is the answer. u may wander, why not hear or baloon cause heat is a gas state which is made up of atom and baloon contains gall like helium which is also made up of atom.
hope this helps u