Answer:
Friction is the main factor which reduces the efficiency of a simple machine. Efficiency of a simple machine can be increased by reducing the friction. But oiling and greasing the machine is a useful way to increase the efficiency of a machine.
Explanation:
Because all machines lose input work to friction, one way to improve the efficiency of a machine is by reducing friction. Oil is used to reduce friction between the moving parts of car engines. The use of oil makes engines more efficient. Another machine that loses input work is a bicycle.
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.
Write the formula of gravitational force between two bodies of masses x and y kept at a distance r
Answer:
F=Gxy/r^2
Explanation:
F=Gm1m2/d^2
F=Gxy/r^2
You plan to use a slingshot to launch a ball that has a mass of 0.019 kg. You want the ball to accelerate straight toward your target at 23 m/s2. How much force do you need to apply to the ball?
Answer:
Explanation:
this is a simple application of Newton's 2nd Law: F = ma.
F = .019(23) so
F = .44 N
You would need to apply a force of 0.437 Newtons to the ball in order to achieve the desired acceleration of 23 m/s².
Force is a physical quantity that describes the interaction between objects or systems and their ability to change motion or shape. It is a vector quantity, meaning it has both magnitude and direction. Force can cause an object to accelerate, decelerate, or change direction.
According to Newton's second law of motion, force is directly proportional to the mass of an object and the acceleration it experiences. The equation F = m × a represents this relationship, where F is the force, m is the mass of the object, and a is the acceleration.
Force can be measured in various units, such as Newtons (N) in the International System of Units (SI) or pounds (lb) in the US customary system. Common examples of forces include gravity, friction, tension, compression, and applied forces like pushing or pulling an object.
According to Newton's second law of motion, which states that force (F) is equal to mass (m) multiplied by acceleration (a):
F = m × a
In this case, the mass of the ball is given as 0.019 kg, and the desired acceleration is 23 m/s². Plugging these values into the equation, we can calculate the force:
F = 0.019 kg × 23 m/s²
F = 0.437 kg m/s²
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Dos carritos se colocan en una mesa sobre la que pueden moverse sin rozamiento y se sujetan comprimiendo un resorte entre ellos. El carrito 1 tiene doble masa que el 2. De pronto se sueltan. A) Compara las velocidades, cantidades de movimiento y energías cinéticas que adquieren, b) ¿Cómo serían las respuestas si la masa del carrito 1 fuese mucho mayor que la del 2?
Answer:
a) v₁ = - ½ v₂, K₁ / K ₂ = ½,)
Explanation:
A) Let's use the conservation of the moment, for this we define the system formed by the spring and the two cars, so the force during the separation is internal, therefore the moment is conserved
initial instant. Before releasing the carts
p₀ = 0
final instant. After jumping the cars
p_f = M v₁ + m v₂₂
how the moment was preserved
p₀ = p_f
0 = M v₁ + m v₂
v₁ = - m / M v₂
indicate that M = 2m
v₁ = - ½ v₂
the kinetic energy of each car is
K₁ = ½ M v₁²
K₁ = ½ 2m (v₂/ 2) ²
K₁ = m ₂v₂² / 4
K₂ = ½ m v₂²
the relationship between the kinetic energies is
K₁ / K₂ = ½
B) If the much greater than the mass of car 1 is mass of car 2
v = - m / M v₂
In this case, the speed of car 1 is very small, so the car 1 practitioner does not backtrack and car 2 leaves with a lot of speed.
The energy is still conserved, where almost all the energy has it is car 2
The wind blows a leaf at 37.9 m/s for 118 s left. How are does the leaf go in that period of time.
A) 3.11 m, left
B) 4470 m, left
C) 80.1 m, left
D) 0.321 m, left
Explanation:
distance = velocity * time
d = 37.9 * 118
distance = 4472.2
When a golfer tees off, the head of her golf club which has a mass of 151 g is traveling 43.9 m/s just before it strikes a 46.0 g golf ball at rest on a tee. Immediately after the collision, the club head continues to travel in the same direction but at a reduced speed of 28.2 m/s. Neglect the mass of the club handle and determine the speed of the golf ball just after impact
Answer:
51.54 m/s
Explanation:
Applying,
Law of conservation of momentum,
Total momentum before collision = Total momentum after collision
mu+m'u' = mv+m'v'.................... Equation 1
Where m = mass of the head of the golf club, m' = mass of the gulf ball, u = initial velocity of the head of the gulf club, u' = initial velocity of the gulf ball, v = final velocity of the head of a gulf club, v' = final velocity of the gulf ball
From the question,
Given: m = 151 g = 0.151 kg, u = 43.9 m/s, m' = 46 g = 0.046 kg, u' = 0 m/s (at rest), v = 28.2 m/s
Substitute these values into equation 1
0.151(43.9)+0.046(0) = 0.151(28.2)+0.046(v')
solve for v'
6.6289+0 = 4.2582+0.046v'
0.046v' = 6.6289-4.2582
0.046v' = 2.3707
v' = 2.3707/0.046
v' = 51.54 m/s
A 45000 watt crane operating at full power lifts a 2100 kg object vertically for 17.4 seconds. How high has the crane lifted the object?
Answer:
Explanation:
We need the power equation here, which is:
Power = (F * Δx)/time
where F * Δx is the amount of work done.
F is a force which is measured in Newtons. We are given the mass of the object, but since we need a Force measure, we need the weight of the object:
F = 2100(9.0)
F = 21000 to the correct number of sig dig.
Now we can plug in the values we have and solve for the displacement, Δx:
[tex]45000=\frac{21000x}{17.4}[/tex] and isolating x:
[tex]\frac{17.4(45000)}{21000}=x[/tex] so
x = 37 m
Dad, if you are seeing this, then I have run away. Angie has been torturing me ever since you started dating her, and I have had enough of it. I have been trying to tell you, but you would never listen. Goodbye, and Angie, if you are seeing this, I posted this on here, so you will not be able to delete anything. Have a nice life
Answer:
hey are you ok!?!?!?!
Explanation:
Is Angie your Dad new gf or wife???
Answer:
:(
Explanation:
u ok?
running away from problems only makes things worse. Your teaching urself to run. but I dont blame u
anyway hope u find what ur looking for out there!!
If a 2.0Ω resistor and a 4.0Ω resistor are connected with a 12 volt battery, what is the total resistance of the circuit?
4.8Ω
9.2Ω
6.0Ω
1.3Ω
what is the pressure exerted, what is the pressure exerted by 50kg girl as she places her weight on one shoe if the heels area is 0.002m²
Answer:
The pressure exerted by the girl is 245,000 N/m²
Explanation:
Given;
mass of the girl, m = 50 kg
area of the girl's shoe, A = 0.002 m²
The pressure exerted by the girl is calculated as follows;
[tex]P = \frac{F}{A} \\\\Where;\\F \ is \ the \ force \ exerted \ by \ girl's \ weight\\\\P = \frac{F}{A} = \frac{mg}{A} = \frac{50 \times 9.8}{0.002} = 245,000 \ N/m^2[/tex]
Therefore, the pressure exerted by the girl is 245,000 N/m²
Que capacidade física consiste em deslocar o corpo no espaço o mais rápido possível, mudando o centro de gravidade de posição, sem perder o equilíbrio e a coordenação dos movimentos?
Answer:ur mom
Explanation:because
A hydrometer is an instrument used to determine liquid density. A simple one is sketched in the figure below. The bulb of a syringe is squeezed and released to lift a sample of the liquid of interest into a tube containing a calibrated rod of known density. (Assume the rod is cylindrical.) The rod, of length L and average density 0, floats partially immersed in the liquid of density . A length h of the rod protrudes above the surface of the liquid. Show that the density of the liquid is given by
=
0L
L − h
.
(Do this on paper. Your instructor may ask you to turn in this work.)
Answer:
weight of rod =weight of liquid displaced
mass of the rod ×g =mass of liquid displaced ×g
(g cancelled out)
mass of the rod =mass of liquid displaced
density of rod ×volume of rod =density of liqiud ×volume of liquid displaced
O×cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface
O×L=density of liquid ×(L-h)
then density of liquid =OL/(L-h) shown as required
The density of the liquid is given by =OL/L − h
What is density?Density is the ratio of mass of an object and its volume.
According to the Archimedes principle, weight of rod = weight of liquid displaced
mass of the rod ×g =mass of liquid displaced ×g
So, mass of the rod =mass of liquid displaced
Mass in terms of density is substituted,
density of rod × volume of rod =density of liquid ×volume of liquid displaced
O× cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface
O×L=density of liquid ×(L-h)
Then, density of liquid =OL/(L-h).
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The two waves shown here are the same distance from point X and are traveling toward each other.
An illustration with a crest 2.0 centimeters high traveling to the right and a second 2.0 centimeters trough traveling toward the left toward point X in the material.
What is the amplitude of the resulting wave when the two waves meet at point X?
0.0 cm
1.0 cm
2.0 cm
4.0 cm
Answer:
(C) on edge.
Explanation:
Answer:
2.0
Explanation:
trust the process.
Using a 100 year time frame,what is the CO2e of 1 tonne of CO2,2 tonne or methane,and 3 tonnes of nitrous oxide
Well, let's see what we've got here:
( 4⁻³ · 3⁴ · 4² ) / ( 3⁵ · 4⁻² ) .
The two simple rules of exponents that we're
going to use here are:
-- Two multiply two numbers with the same base,
add their exponents. Like (A³) · (A²) = A⁵ .
But the bases have to be the same.
-- A negative power just means it belongs in the
other section of a fraction.
A negative power on top means it belongs on the bottom.
A negative power on the bottom means it belongs on top.
Like A⁻² means 1/A² . And 1/B⁻³ means B³ .
That's all you need in order to clean up the big fraction
in the question. But in order to see where you can use
these rules, you need to re-arrange things first.
Original: ( 4⁻³ · 3⁴ · 4² ) / ( 3⁵ · 4⁻² )
Let's send the 4⁻³
to the bottom
where it belongs: ( -- 3⁴ · 4² ) / 4³ · ( 3⁵ · 4⁻² )
Not take that 4⁻² from
the bottom, and put it on
top, where it belongs: ( 4² · 3⁴ · 4² ) / 4³ · ( 3⁵ -- )
Multiply the 4²s on top: ( 4⁴ · 3⁴ ) / ( 4³ · 3⁵ )
Now let me break this up.
Not changing anything, just
writing it in a different way: ( 4⁴ / 4³ ) · ( 3⁴ / 3⁵ )
Look at the first fraction: 4⁴ / 4³ .
Divide top and bottom by 4³ , and it becomes just 4 .
Now look at the second fraction: 3⁴ / 3⁵ .
Divide top and bottom by 3⁴ , and it becomes just 1/3 .
So in the end, we're left with just 4 / 3 .
And THAT is exactly equal to the original big messy fraction
in the question. It has exactly the same numerical value, but
you'd never know it when you see it, because it's a lot simpler.
There are a lot of other ways we could have manipulated and
massaged the original fraction, but the steps are the same:
-- Multiply numbers with the same base, by adding the exponents.
-- Remember that a number with a negative exponent belongs
in the other section of the fraction, with a positive exponent.
a petrol engine raises 200kg of water in well from a depth of 7m in 6s show that the engine is developed about 2.33 kw of power
Answer:
P = 2.33 kW
Explanation:
Given that,
Mass, m = 200 kg
It is raises in the well from a depth of 7 m in 6 s.
W e know that,
Power = work done/time
Put all the values,
[tex]P=\dfrac{mgh}{t}\\\\P=\dfrac{200\times 10\times 7}{6}\\\\P=2333.3\ W[/tex]
or
P = 2.33 kW
Hence, the power of the engine is 2.33 kW.
What is a sound wave?
Which circuit component usually acts as a switch or amplifier?
O A. A transistor
O B. A capacitor
O C. A resistor
D. A battery
Answer:
The answer is A. A transistor
Answer:
a transistor
Explanation:
A P E X
According to Archimedes' principle, when will an object float in water?
A. When its volume is less than the volume of water it displaces
B. When its weight is equal to the buoyant force exerted by the water
C. When its density is greater than the density of water
D. When its weight is greater than the weight of water it displaces
Answer:
Its B
Explanation:
a p e x
The process of recovering valuable or useful materials from waste or scrap is called
a.
recycling.
c.
rebuilding.
b.
renewing.
d.
reducing.
Please select the best answer from the choices provided
A
B
C
D
Answer:
hi
Explanation:
what are the horizontal and vertical components of a vector that is 25units long with an angle of 130 degrees
Answer:
The horizontal component of the vector is approximately -16.07
The vertical component of the vector is approximately 19.15
Explanation:
A vector quantity is a quantity that posses both magnitude and direction specifications
The magnitude of the given vector, R = 25 units
The direction of the vector, θ = 130°
Therefore the location of the vector, starting from the origin of the Cartesian plane, is in the second quadrant having an angle of 180° - 130° = 50° to the horizontal
Given that the x-coordinate is negative in the second quadrant, we have;
The horizontal component of the vector, Rₓ = The x-coordinate of the vector = R×cos(θ)
∴ The horizontal component of the vector, Rₓ = 25 × cos(130°) = -25 × cos(50°) ≈ -16.07
The horizontal component of the vector, Rₓ ≈ -16.07
The vertical component of the vector, [tex]R_y[/tex] = The y-coordinate of the vector = R×sin(θ)
∴ The vertical component of the vector, [tex]R_y[/tex] = 25 × sin(130°) ≈ 19.15
The vertical component of the vector, [tex]R_y[/tex] ≈ 19.15
The vector can be resolved as R = -16.07·i + 19.15·j
A 40kg girl and a 50kg boy are facing each other on a friction-free rollerskates. The girl pushes the boy, who moves away at a speed of 3 m/s. What is the girl's
speed?
Your answer
Answer:
Explanation:
The Law of Momentum Conservation, just like the Law of Thermodynamics about energy, says that momentum is neither created nor destroyed but is conserved, meaning it has to go somewhere. If the girl pushes the boy and they are both on friction free skates, then the girl will also react to the push. Momentum Conservation says
[tex](m_gv_g+m_bv_b)_b=(m_gv_g+m_bv_b)_a[/tex] In words this says that the mass times the velocity of the girl plus the mass times the velocity of the boy before the push has to equal the mass times velocity of the girl plus the mass times velocity of the boy after the push. Mathematically,
[tex](40.0*0+50.0*0)_b=(40.0v+50.0*-3)_a[/tex]
The left side of this is equal to 0. On the right, I made the velocity of the boy negative. We could have made it positive and it wouldn't have mattered. The sign will only be important to the result because if the sign of the girl's velocity is the same as the boy's, she is moving in the same direction as he is; if it's different, she is moving in the opposite direction.
0 = 40.0v - 150.0 and
-40.0v = -150.0 so
v = 3.75 This means that when she pushes the boy one way, mometum is conserved and she moves in the opposite direction and at a greater velocity (because her mass is less). Physics is a wonderful thing, isn't it!?
If you want to decrease the current created by a generator what can you do?
Answer:
To decrease the current;
1) Use fewer loops or number of turns
2) Use a lower speed of rotation of the coil in the magnetic field
3) Use a weaker magnetic
Explanation:
According to Faraday's Law of induction, which is the basis of the electromagnetism, electromagnetic induction and therefore the basis of the electric generator, can be written as follows;
[tex]\epsilon = -N \cdot \dfrac{\Delta \phi}{\Delta t}[/tex]
Where;
ε = The induced voltage
N = The number of turns (loops)
ΔФ = The change in the magnetic flux
Δt = The change in the time (the duration)
Given that voltage is directly related to the current, decreasing the voltage, decreases the current
To decrease the voltage, and therefore, the current we can;
1) Reduce the number of loops in the coil
2) Increase the time change per unit change in flux by slowing down the speed of rotation of the generator
3) Decrease the amount of change in the magnetic field per turn, by using a weaker magnetic
hey everyone
what is optics??
Explanation:
Optics is a branch of physics that is the study of light and vision. ... The branch of physics dealing with the nature and properties of electromagnetic energy in the light spectrum and the phenomena of vision. In the broadest sense, optics deals with infrared light, visible light, and ultraviolet light.
need help with this!
just scienceeeeeee
Answer:
7) λ = 0.5 m, 8) f = 4.8 10¹⁴ Hz
Explanation:
The speed of an electromagnetic wave is
c = λ f
where c is the speed of light in vacuum c = 3 10⁸ m / s
7) indicate the frequency f = 6.0 10⁸ Hz
we do not know the wavelength
λ = c / f
we calculate
λ = 3 10⁸ / 6.0 10⁸
λ = 0.5 m
8) indicate the wavelength λ = 6.25 10-7 m
we do not know the frequency
f = c / λ
we calculate
f = 3 10⁸ / 6.25 10⁻⁷
f = 0.48 10¹⁵ Hz
f = 4.8 10¹⁴ Hz
Which of the following describes the work done by a heat engine?
A. Qin - Qout
B. Qin - W
C. Qout - Qin D. Qin + Qout
Answer: A.
Explanation:
Máquina térmica tem como função, manter a temperatura de um dado fluído, então, a quantidade de calor desse mesmo fluído ao entrar na máquina, será igual á quantidade de calor desse fluido saindo.
Qin - Qout describes the work done by a heat engine. Hence option A is correct.
What is heat engine ?A heat engine is a system which converts heat into useful work. Carnot engine is an ideal engine which has maximum efficiency than any other engines. Carnot has showed that "no engine can be more efficient than Carnot engine and the 100% efficient engine can not be existed". It takes heat from the reservoir to do some work and it discharges some amount of heat to the sink. Reservoir is know as hot body and sink is know as cold body.
Efficiency of the Carnot's heat engine is given by,
Efficiency, η = Work done / Heat input
Work done, W = Q1 – Q2
Heat input = Q1
Efficiency,
η = W / Q1
= (Q1 – Q2) / Q1
=1 – (Q2 / Q1).
To have engine with 100% efficiency, Q2 must be zero and it is not possible.
Hence work done by a heat engine is Qin - Qout.
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A ball is rolling along a straight and level path. The ball is traveling at a constant speed of 2.0 m/s. The mass of the ball is 3.0 kg. What is the kinetic energy of the ball?
A. 6.0 J
B. 9.0 J
C. 12.0 J
D. 3.0 J
Please help me :))
Which golf ball would hit the surface with the greatest impact: a ball that fell one meter above the surface of the Earth or a ball that fell one meter above the surface of the Moon?
Answer:
the one above the surface of earth
Explanation:
earth has gravity the ball of the moon would float away
A piece of glass has mass of 1 kg and a density of 800 kgm-³ negative cubed calculate its volume
Explanation:
we know that
v = m/d
or; v=1kg/800kgm^3
or; v=0. 00125m
Do solar panels create enough energy to power the car throughout the day?
Answer:
Yes, but only if it's sunny.
Explanation:
As you know, solar panels generate energy through the sun's rays of light (better known as sunlight). Therefore, as long as the sun is shining high in the sky, the car will generate electricity and be able to function. If this vehicle was only powered by solar panels, it would not function during the night, in cloudy areas, and/or in dark places (such as parking garages or home garages).
Hope this helps!
Draw Lewis diagram of an oxygen difluoride molecule
Explanation:
that is my answer thank me later
Answer:
oxygen difluoride a polar molecule
