The formula you mentioned is known as the dot product formula or the scalar product formula. It is used to find the angle between two vectors u and v.
Let's start by defining the vectors u and v. Suppose we have two vectors u and v in a two-dimensional space.
u = (u1, u2)
v = (v1, v2)
The dot product of these vectors is defined as:
u . v = |u| |v| cos(β)
where |u| and |v| are the magnitudes of the vectors u and v respectively, and β is the angle between the vectors u and v.
Now, let's derive this formula. The dot product of two vectors u and v is given by:
u . v = (u1 × v1) + (u2 × v2)
The magnitude of a vector is given by:
|u| = sqrt(u1² + u2²)
|v| = sqrt(v1² + v2²)
We can use the dot product and magnitude equations to obtain:
cos(β) = (u . v) / (|u| × |v|)
Multiplying both sides by |u| × |v| gives us:
|u| × |v| × cos(β) = u . v
Therefore, we have derived the dot product formula:
u . v = |u| × |v| × cos(β)
This formula can be used to find the angle between two vectors u and v in any two-dimensional or three-dimensional space.
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The complete question is-
Write the proof of the formula
u.v=|u||v|cosβ
A flower as an object in front of a convex mirror. A smaller upright flower closer to the mirror. A smaller upright flower close to the mirror on the other side of the mirror. An inverted smaller flower on the on the other side of the mirror just past the focal point. An inverted flower the same size as the object right below it.
Which flower would most likely represent the image formed by the mirror? Justify your answer.
Answer:
There are 13 a
Explanation:
That's the answer how many a r there
Answer:
the convex mirror will produce image 3. the image is virtual and is now behind the mirror and it becomes smaller but remains upright.
Explanation:
The low-frequency speaker of a stereo set has a surface area of and produces 1W of acoustical power. What is the intensity at the speaker
Answer:
I = [tex]\frac{1}{4\pi \ r^2}[/tex]
we see the intensity decreases with the inverse of the distance squared
Explanation:
Intensity is defined as power per unit area,
I = P / A
in this case we have that the sound is emitted in a spherical form therefore the area is
A = 4 pi r2
therefore the intensity is
I = [tex]\frac{1}{4\pi \ r^2}[/tex]
as we see the intensity decreases with the inverse of the distance squared
A motorcyclist is making an electric vest that, when connected to the motorcycle's 12 V battery, will warm her on cold rides. She is using 0.25-mm-diameter copper wire, and she wants a current of 4.2 A in the wire. Part A What length wire must she use
Answer:
L = 8.35 m
Explanation:
The lenght of a wire L can be calculated using the following expression:
L = R A/ρ (1)
Where:
R: resistance of the wire
A: Cross section area of the wire
ρ: resistivity of the copper wire.
With this expression we realize that we do not have the area of the cross section, and the resistance of the wire either.
To calculate the area we can use the following expression:
A = πr² (2)
If the diameter is 0.25 mm, then the radius is half, 0.125 mm. Converting this in meter it will have to be:
0.125 /1000 = 0.000125 m
Replacing we have:
A = π(0.000125)²
A = 4.91x10⁻⁸ m²
The reported resistivity of a copper wire is 1.68x10⁻⁸ Ω.m, so we just need to determine the resistance, which can be found using Ohm's law:
R = V/I (3)
Replacing (3) into (1) we have:
L = (V * A) / (I * ρ) (4)
So finally, the length of the copper wire will be:
L = (12 * 4.91x10⁻⁸) / (4.2 * 1.68x10⁻⁸)
L = 8.35 mHope this helps
I love you
Please answer my question :-)
Answer:
A- Astronomical body
C- Galaxy
D- Comet
B- Moon
Hope this helps you! Have a great day!
Answer:
1. A
2. C
3. D
4. B
Explanation:
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Answer:
b
Explanation:
this because if force (f) are resultant cos then the point is proportional to the direction of c at greatest possible forces
What was the average speed in km/h of a car that travels 788 km in 7.1 h?
Answer:
Well the answer is 111 (rounded) km/h
Explanation:
788/7.1 is 110.9... so if you round it it would equal 111.
Which of the following helps prevent and cope with heat-related conditions?
Drinking water
Wear proper clothing
Rest frequently
all of the above
An action which would help in preventing and coping with heat-related conditions is: A. Drinking water.
What is heat?Heat can be defined as a form of energy that is transferred from a physical object (body) to another, as a result of a difference in temperature. Also, heat is a condition of weather that is generally characterized by a high degree of temperature.
This ultimately implies that, heat is most likely to cause dehydration and high body temperature.
In order to prevent and cope with heat-related conditions, you should ensure that you drink water at regular intervals for hydration.
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The blood pressure at your heart is approximately 100 mm Hg. As blood is pumped from the left ventricle of your heart, it flows through the aorta, a single large vessel with a diameter of about 2.5 cm. The speed of blood flow in the aorta is about 60 cm/s. Any change in pressure as blood flows in the aorta is due to the change in height: the vessel is large enough that viscous drag is not a major factor into successively smaller and smaller blood vessels until it reaches the capillaries. Blood flows in the capillaries at the much lower speed of approximately 0.7 mm/s. The diameter of capillaries and other small blood vessels is so small that viscous drag is a major factor..Because the flow speed in your capillaries is much less than in the aorta, the total cross-section area of the capillaries considered together must be much larger than that of the aorta. Given the flow speeds noted, the total area of the capillaries considered together is equivalent to the cross-section area of a single vessel of approximately what diameter?
a. 25 cm
b. 50 cm
c. 75 cm
d. 100 cm
Answer:
The correct option is c. 75 for this question
Explanation:
The correct option is c. 75 for this question:
Let's see how.
Continuity Equation is given as:
AcVc = AaVa
Where,
Aa = Area of Aorta
Ac = Area of the capillary
Va = Fluid speed in Aorta
Vc = Fluid speed in Capillary
So,
Assuming the fluid is the ideal one/
[tex]\pi[/tex]/4 [tex]Dc^{2}[/tex] Vc= [tex]\pi[/tex]/4 [tex]Da^{2}[/tex] Va
[tex]Dc^{2}[/tex] Vc= [tex]Da^{2}[/tex] Va
Dc = Da x [tex]\sqrt{\frac{Va}{Vc} }[/tex]
Dc = 2.5 cm x [tex]\sqrt{\frac{60 cm}{0.07 cm } }[/tex]
Dc = 73.192 cm
Dc = 75 approximately
Hence, the diameter of the capillary = 75 cm approximately
Semiconductors can simplistically be thought of as an intermediate state between insulators and conductors. In a semiconductor, charges are normally bound in place (like in an insulator), but when injected with enough energy, the charges can move freely (like in a conductor). Given what we have observed about the behavior of conductors and insulators in this exploration, what would happen if we replaced the glass rod with a semiconductor material
Answer:
The semiconductor rod will conduct electricity
Explanation:
Glass rod does not conduct electricity. Glass is one of the best insulators of electricity. But when a glass rod is replace with a semi conductor, then the semi conductor rod starts conducting electricity as the electrons are free to move.
Semi conductors are special materials in which the energy band lies in between the conductor and the non conductor. The conductivity of a semi conductor increases with the increasing temperature.
In an semi conductor the electrons are free to move and as they starts moving they conduct electricity. Thus a semi conductor rod replacing a glass rod conducts electricity.
What is the equivalent resistance of this network?
The equivalent resistance of the circuit network is determined as 1.6 ohms.
What is the equivalent resistance of the network?The equivalent resistance of the circuit network is calculated as follows;
To determine the equivalent resistance of the circuit, we will decompose the circuit into series and parallel components.
The equivalent resistance at J₄ is calculated as follows;
The two 4 ohms are in series;
J₄ = 4Ω + 4 Ω = 8 Ω
The equivalent resistance at J₁ is calculated as follows;
The 4 ohms and 0 ohm are in series;
J₁ = 0 Ω + 4 Ω = 4 Ω
The equivalent resistance at J₂ and J₃ is calculated by applying the formula for parallel resistors;
1/Re = 1/J₁ + 1/J₄ + 1/J₂,₃
1/Re = 1/4 + 1/8 + 1/4
1/Re = 5/8
Re = 8/5
Re = 1.6 ohms
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Q4. (a) An acre-foot is the volume of water that would cover 1 acre of flat land to a depth of 1
foot. How many gallons are in 1 acre-foot?
Answer:
326,000
Explanation:
One acre-foot equals about 326,000 gallons, or enough water to cover an acre of land, about the size of a football field, one foot deep. An average California household uses between one-half and one acre-foot of water per year for indoor and outdoor use.
A Van de Graaff generator is one of the original particle accelerators and can be used to accelerate charged particles like protons or electrons. You may have seen it used to make human hair stand on end or produce large sparks. One application of the Van de Graaff generator is to create x-rays by bombarding a hard metal target with the beam. Consider a beam of protons at 1.10 keV and a current of 4.65 mA produced by the generator.
(a) What is the speed of the protons?
(b) How many protons are produced each second?
Solution :
Given that :
The energy of the protons, K.E. = 1.10 keV
[tex]$= 1.10 \times 10^3 \ eV $[/tex]
The current produced by the generator is I = 5 mA
[tex]$= 5 \times 10^{-3} \ A$[/tex]
Now [tex]$1 \ eV = 1.6 \times 10^{-19 }\ J$[/tex]
Mass of the proton, m = [tex]$1.67 \times 10^_{-27} $[/tex] kg
Charge of the proton, [tex]$q_p = 1.6 \times 10^{-19} \ C$[/tex]
a). Therefore using the formula for K.E. we can find out the velocity of the proton.
[tex]$K.E. =\frac{1}{2}mv^2$[/tex]
[tex]$v=\sqrt{\frac{2K.E.}{m}}$[/tex]
[tex]$v=\sqrt{\frac{2\times 10^3 \times 1.6 \times 10^{-19}}{1.67 \times 10^{-27}}}$[/tex]
[tex]$= 4.38 \times 10^5 \ m/s$[/tex]
b). We know that the current is :
[tex]$I=\frac{\Delta Q}{\Delta t}$[/tex]
Therefore, the total charge in one second is given by :
[tex]$\Delta Q = I \times \Delta t$[/tex]
[tex]$= 5 \times 10^{-3} \times 1$[/tex]
[tex]$= 5 \times 10^{-3}\ C$[/tex]
So, the number of protons in this charge is given by :
[tex]$n = \frac{\Delta Q}{q_p}$[/tex]
[tex]$=\frac{5 \times 10^{-3} }{1.6 \times 10^{-19}}$[/tex]
[tex]$= 3.13 \times 10^{16}$[/tex] protons
how is work and energy inter-related?? (in simple words)
Answer:
The work and energy is inter- related because if we are energetic then only we are able to work.
People who are weak and not energetic cannot work continuously.
Explanation:
hope this helps you....
The map below shows major ocean currents in the North Atlantic and North Pacific Oceans. In general, currents flowing toward the
Equator bring cooler waters to some regions, while currents flowing away from the Equator bring warmer waters to other regions.
North
British
Isles
Askan
North Atlantic
Azor
U.S.A
California
Gulf Stream
Loop
n
Canbean
North Equatorial
North Equatorial CC
North Fuatorial
Equator
South Equatorial
Not
South Equatorial
Image courtesy of NOAA
Judging from the map, which region probably has cooler summers than it would without the effect of a nearby ocean current?
A the Central U.S.
B. the British Isles
C. the U.S. East Coast
D. the US West Coast
Answer:
d
Explanation:
the US West Coast region probably has cooler summers than it would without the effect of a nearby ocean current.
what is ocean current ?
ocean current can be defined as the horizontal movement of seawater which is produced by gravity, wind, and water density, it play an major role in the determination of climates of coastal regions.
The movement of ocean water is continuous which can be up three types such as Waves, Tides, Currents
The streams of water which flow continuously on the ocean surface in specific directions are called ocean currents, it affect the temperature of ocean water as Warm ocean currents increase the temperature whereas Cold ocean currents decrease the temperature.
The magnitude of the ocean currents is about few centimeters per second to as much as 4 metres per second and the intensity of the ocean currents generally decreases with increasing depth.
There are two types of ocean currents such as Warm Ocean Currents
and Cold Ocean Currents
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Stacy collected the data shown in the table.
Number of Washers Total Mass Total Force
0.6 kg 5.9 N
2
1.2 kg 11.8 N
3
1.8 kg 17.6N
4
2.5 kg 24.5 N
5
3.2 kg 31.4 N
What's the general relationship between mass and gravitational force?
Answer:
1.8 Kg 17.6N
Explanation:
I don't know the explanation hahaha
Answer:
The gravitational force on an object increases as the object’s mass increases.
Explanation:
This is the answer on Edmentum. :)
Assuming 84.0% efficiency for the conversion of electrical power by the motor, what current must the 13.0-V batteries of a 716 kg electric car be able to supply to climb a 3.00 x 102 m high hill in 2.00 min at a constant 22.0 m/s speed while exerting 7.00 x 102 N of force to overcome air resistance and friction
Answer:
[tex]\mathbf{ current(I) =1766.67 \ A}[/tex]
Explanation:
Given that:
The air resistance and friction = 700 N
The gravity caused force = 716 × 9.8 = 7016.8
Total force = (7016.8 + 700) N
Total force = 7716.8 N
∴
[tex]13 \times current(I) \times 0.84 = \dfrac{7716.8 \times 300}{2 \times 60}[/tex]
[tex]current(I) \times 10.92= 19292[/tex]
[tex]current(I) = \dfrac{19292}{10.92}[/tex]
[tex]\mathbf{ current(I) =1766.67 \ A}[/tex]
Work is a measurement of the transfer of which of the following?
A. Impulse
B. Power
C. Energy
Answer:Enegry
Explanation:Energy transfer is used to do work
A 0.15 kg baseball is traveling at 40 meters per second (about 90 miles per hour) if the ball comes to a complete stop when it hits the catchers mitt, what is the change in velocity?
Answer:
Please find attached pdf
Explanation:
A steel cylinder of length 10 cm, mass 160 g and density 8 g/em. The radius of the cylinder is
Answer:
0.8cm
Explanation:
Volume = mass/density = 160/8 = 20cm³
Volume = πr²h
r² = v/πh = 20/10π =0.64
r = √0.64 = 0.8
A car starts from rest at a stop sign. It accelerates at 2.0 m/s2 for 6.2 seconds, coasts for 2.5 s , and then slows down at a rate of 1.5m/s2 for the next stop sign. How far apart are the stop signs
Answer:
the distance between the stop signs is 120.7 m.
Explanation:
The car moved in three stages;
(1) It accelerates from rest at 2.0 m/s² for 6.2 seconds
(2) it moved at a constant speed for 2.5 s
(3) it finally decelerate at the rate of 1.5m/s²
(1) The distance moved by the car during the first stage;
s₁ = ut + ¹/₂at²
s₁ = 0 + ¹/₂ (2)(6.2)²
s₁ = 38.44 m
(2) The distance moved by the car during the second stage;
calculate the constant speed of the car,
v = u + at
v = 0 + 2 x 6.2
v = 12.4 m/s
The distance moved by the car as it coasts for 2.5s: s₂ = vt
s₂ = 12.4 x 2.5
s₂ = 31 m
(3) The distance moved by the car during the third stage;
When the car stops, the final velocity is zero.
v² = u² + 2as₃
a = -1.5 m/s², since the car slowed down or decelerated.
0 = 12.4² + (2 x - 1.5)s₃
0 = 153.76 - 3s₃
3s₃ = 153.76
s₃ = 153.76 / 3
s₃ = 51.253 m
The total distance moved by the car from the start to stop = s₁ + s₂ + s₃
d = 38.44 m + 31 m + 51.253 m
d = 120.7 m
Therefore, the distance between the stop signs is 120.7 m.
Which of the following is a part of both geocentric model and heliocentric model
Answer:
These planets rotate around the sun in a circular path. Likewise in a heliocentric model it is believed that the sun is at the center of the universe and the planet earth along with all other planet move around it. Thus in both geocentric model and heliocentric model bodies in space move in circular orbits.
Answer:
The bodies in space move in circular orbits
Explanation:
I got it right on my test
In the human arm, the forearm and hand pivot about the elbow joint. Consider a simplified model in which the biceps muscle is attached to the forearm 3.80 cm from the elbow joint. Assume that the person's hand and forearm together weigh 15.0 N and that their center of gravity is 15.0 cm from the elbow (not quite halfway to the hand). The forearm is held horizontally at a right angle to the upper arm, with the biceps muscle exerting its force perpendicular to the forearm.
A. Find the force exerted by the biceps when the hand is empty.
B. Now the person holds a 80.0-N weight in his hand, with the forearm still horizontal. Assume that the center of gravity of this weight is 33.0 cm from the elbow. Find the force now exerted by the biceps.
C. Explain why the biceps muscle needs to be very strong.
D. Under the conditions of part B, find the magnitude of the force that the elbow joint exerts on the forearm.
E. Under the conditions of part B, find the direction of the force that the elbow joint exerts on the forearm.
F. While holding the 80.0-N weight, the person raises his forearm until it is at an angle of 53.0∘ above the horizontal. If the biceps muscle continues to exert its force perpendicular to the forearm, what is this force when the forearm is in this position?
G. Has the force increased or decreased from its value in part B? Explain why this is so, and test your answer by actually doing this with your own arm.
Answer:
Answer is explained in the explanation section below.
Explanation:
Part A)
From conserve moment of force, we have:
F1d1 = F2d2
F1 x (3.80 x [tex]10^{-2}[/tex] m) = 15N x (15 x [tex]10^{-2}[/tex] m)
F1 = [tex]\frac{15 . 15 . 10^{-2} }{3.80 . 10^{-2} }[/tex]
F1 = 59.2 N
Force exerted by the biceps when the hand is empty.
Part B)
The 80 N weight acts at 33 cm and 15 N at 15 cm, then the center of mass is:
x = [tex]\frac{m1x1 + m2x2}{m1+m2}[/tex]
x = [tex]\frac{\frac{80}{9.8} (33 .10^{-2}) + \frac{15}{9.8}(15.10^{-2} }{\frac{80}{9.8} + \frac{15}{9.8} }[/tex]
x = 30.16 x [tex]10^{-2}[/tex] m
Total Weight is:
F = 80N + 15N = 95N
From the conserve moment of force, we have:
F ( 3.8 x [tex]10^{-2}[/tex] ) = 95N (30.16 x [tex]10^{-2}[/tex])
F = 754 N
Part C:
From the above two examples solved, the force exerted by the biceps is higher than downward force, due to this muscle need to be very strong.
Part D)
The force exerted by elbow on the forearm is:
The force exerted by the elbow and biceps are in upward direction and total weight is in downward direction. So, the balancing force in vertical direction is:
F2 + 754N = 95N
F2 = 95N -754N
F2 = -659N
Negative sign shows the force is in downward direction.
Part E)
The bicep muscle acts perpendicular to the forearm, so it is lever arm stays the same. but those of the other two forces decreases as the arm is raised. There tension in the biceps muscle decreases.
Part F)
Angle = 53 degrees.
So,
Force = FcosФ
Force = 754 cos 53
Force = 453.76 N
Part G)
The value of force has gone downwards. It has decreased from that of part B.
a girl whose mass is 40kg walk up a flight of 20steps each 15mm hight in 10seconds.find power developed by the girl showing the solution
Answer: Approximately 11.76 joules per second
=========================================================
Work Shown:
Mass = 40 kg
Force pulling down = (mass)*(gravity) = 40*9.8 = 392 newtons
Roughly 392 newtons of force are pulling down on her.
To climb the steps, she must apply 392 newtons of force upward.
---------------
Displacement = 20*(15 mm) = 300 mm = 0.3 m
Work = Force*Displacement
Work = 392*0.3
Work = 117.6 joules of energy
---------------
Power = (Work)/(Time)
Power = (117.6 joules)/(10 seconds)
Power = (117.6/10) joules per second
Power = 11.76 joules per second, which is approximate
cylindrical electric resistance heater has a diameter of 1cm and length of 0.25m. When air at 25oC flows across the heater a heat-transfer coefficient of 25W/(m2 . oC) exists at the surface. (JUSTIFY ANY ASSUMPTIONS YOU IMPOSE!) a) If the electrical input to the heater is 5W, what is the steady state surface temperature of the heater if radiation is assumed negligible
Answer:
Explanation:
From the information given:
The diameter of the cylindrical heater (d) = 1 cm
The length of the cylindrical heater (l) = 0.25 m
The ambient air temperature [tex](T_{\infty})[/tex] = 25° C= (273+25)K = 298 K
The convective heat transfer coefficient (h) = 25 W/m² °C
The electric input Q = 5W
As stated in the question that if radiation is being neglected:-
Let also assume that;
the heat transfer takes place at a steady-state
1-D flow takes place
No external heat generation; &
No force convection takes place;
Then; the heat transfer through the convection can be calculated as:
[tex]Q = hA(T - T_{\infty})[/tex]
[tex]5= 25 \times (\pi \times (1\times 10^{-2}) \times 0.25) (T -0.25)[/tex]
By solving the above calculation:
T ( surface temperature of the heater) = 50.46° C 122.83° F
Two students on ice skates stand one behind the other. Student 2 pushes student 1 in the back; student 1 has less mass than student 2; student 1 has a great acceleration than student 2. which law of motion is this (Newton's laws)
Answer:
law in acting
Explanation:
If a shopping cart is pushed by a person exerting 50 J of work on it, what is the energy transfer to the shopping cart if it has a mass of 2 kg?
A. 52 J
B. 50 J
C. 25 J
Answer:
B
Explanation:
Plzz answer correctly
How does altitude from the surface of earth affect the time period of a simple pendulum
Answer:
because the strength of Earth's gravitational field is not uniform everywhere, a given pendulum swings faster, and thus has a shorter period, at low altitudes and at Earth's poles than it does at high altitudes and at the Equator.
two small identical conducting spheres have charges of 2.0x10-9C and - 0.5x109 C respectively when they are placed 4cm apart, what is the force between them? If they are brought into contact and then separated by 4cm, what is the force between them?
Answer:
6
Explanation:
nothingnsbejejjdbsbzbawkje
One species of eucalyptus tree, Eucalyptus regnans, grow to heights similar to those attained by California redwoods. Suppose a bird sitting on top of one specimen of eucalyptus tree drops a nut that is 1.7 ounces. If the speed of the falling nut at the moment it is 50.3 m above the ground is 42.7 m/s, how tall is the tree
Answer:
The tree is 143.325 meters tall
Explanation:
The given parameters of the eucalyptus tree are;
The mass of the eucalyptus tree nut = 1.7 ounces
The speed of the nut at 50.3 m above the ground, v = 42.7 m/s
The equation for free fall is given as follows;
v² = 2·g·h
Where;
v = The velocity after falling through a height, h
g = The acceleration due to gravity = 9.8 m/s²
h = The height through which the seed has already fallen
Therefore, we have;
h = v²/(2·g) = (42.7 m/s)²/(2 × 9.8 m/s²) = 93.025 m
The height through which the seed has already fallen, h = 93.025 m
The height of the tree = h + The height of the seed above ground at the moment it was falling at 42.7 m/s
The height of the tree = 93.025 m + 50.3 m = 143.325 m
The height of the tree = 143.325 m.
The height of the eucalyptus tree is approximately 111.9 meters.
To determine the height of the tree, we can use the equations of motion. The initial velocity of the nut, u, is 0 m/s (since it is dropped), the acceleration due to gravity, a, is approximately 9.8 m/s², and the final velocity, v, is 42.7 m/s. We need to find the height, h. Using the equation v² = u² + 2a(h - u), we can rearrange it to solve for h: h = (v² - u²) / (2a) Plugging in the values, we get: h = (42.7² - 0²) / (2 * 9.8) = 111.9 meters Therefore, the height of the eucalyptus tree is approximately 111.9 meters.
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