Answer:
false.
Explanation:
Ok, we define average velocity as the sum of the initial and final velocity divided by two.
Remember that the velocity is a vector, so it has a direction.
Then when she goes from the 1st end to the other, the velocity is positive
When she goes back, the velocity is negative
if both cases the magnitude of the velocity, the speed, is the same, then the average velocity is:
AV = (V + (-V))/2 = 0
While the average speed is the quotient between the total distance traveled (twice the length of the pool) and the time it took to travel it.
So we already can see that the average velocity will not be equal to half of the average speed.
The statement is false
14. What's one of the two requirements electric current?
A. There must be an electric potential between two bodies
B. There must be no valence electrons that make their element unstable
C. There must be a carbon element present in the electric current
D. There must be a magnetic force between two bodies
Marko
One of the two requirements of electric current is there must be an electric potential between two bodies
For electric current to flow, there must be an electric potential between two bodies.
This is because electric charge flows from a higher electric potential to a lower electric potential just as, water flows from a higher gravitational potential to a lower gravitational potential.
The difference between the electric potential between the two bodies causes the electric charge to flow between the two bodies.
This flow of electric charge constitutes electric current and electric current will only flow when there is an electric potential between two bodies.
So, one of the two requirements of electric current is there must be an electric potential between two bodies.
So, the answer is A
Learn more about electric current here:
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As a skydiver accelerates downward, what force increases? A. Gravity B. Thrust C. Air resistance D. Centripetal
Answer:
(A) Gravity is you're answer.
Explanation:
When an object or human is falling at an increased rate, The force of gravity is taking place.
Identify 2 different ways that data can be displayed or represented.
Answer:
tables, charts and graphs
Explanation:
A generator uses a coil that has 270 turns and a 0.48-T magnetic field. The frequency of this generator is 60.0 Hz, and its emf has an rms value of 120 V. Assuming that each turn of the coil is a square (an approximation), determine the length of the wire from which the coil is made.
Answer:
The total length of wire is 0.24 m.
Explanation:
Number of turns, N = 270
magnetic field, B = 0.48 T
frequency, f = 60 Hz
rms value of emf = 120 V
maximum value of emf, Vo = 1.414 x 120 = 169.68 V
let the area of square is A and the side is L.
The maximum emf is given by
Vo = N B A w
169.68 = 270 x 0.48 x A x 2 x 3.14 x 60
A = 3.5 x 10^-3 m^2
So,
L = 0.0589 m
Total length of wire, P = 4 L = 4 x 0.0589 = 0.24 m
why meter cube is called derived unit
Answer:
Because it is the result of two more fundamental units, a derived unit is termed that. For volume, the cubic meter (m³) is the fundamental unit of area. Any number that cannot be measured directly with any equipment is referred to as a derived unit. For example, we can't quantify a substance's density using a rule, scale, or bucket.
OAmalOHopeO
The capacitor is now disconnected from the battery, and the dielectric plate is slowly removed the rest of the way out of the capacitor. Find the new energy of the capacitor, U3. Express your answer numerically in joules.
The question is incomplete. The complete question is :
A dielectric-filled parallel-plate capacitor has plate area A = 10.0 cm2 , plate separation d = 10.0 mm and dielectric constant k = 3.00. The capacitor is connected to a battery that creates a constant voltage V = 15.0 V . Throughout the problem, use ϵ0 = 8.85×10−12 C2/N⋅m2 .
Find the energy U1 of the dielectric-filled capacitor. I got U1=2.99*10^-10 J which I know is correct. Now I need these:
1. The dielectric plate is now slowly pulled out of the capacitor, which remains connected to the battery. Find the energy U2 of the capacitor at the moment when the capacitor is half-filled with the dielectric.
2. The capacitor is now disconnected from the battery, and the dielectric plate is slowly removed the rest of the way out of the capacitor. Find the new energy of the capacitor, U3.
Solution :
Given :
[tex]A = 10 \ cm^2[/tex]
[tex]$=0.0010 \ m^2$[/tex]
d = 10 mm
= 0.010 m
Then, Capacitance,
[tex]$C=\frac{k \epsilon_0 A}{d}$[/tex]
[tex]$C=\frac{8.85 \times 10^{12} \times 3 \times 0.0010}{0.010}$[/tex]
[tex]$C=2.655 \times 10^{12} \ F$[/tex]
[tex]$U_1 = \frac{1}{2}CV^2$[/tex]
[tex]$U_1 = \frac{1}{2} \times 2.655 \times 10^{-12} \times (15V)^2$[/tex]
[tex]$U_1=2.987 \times 10^{-10}\ J$[/tex]
Now,
[tex]$C_k=\frac{1}{2} \frac{k \epsilon_0}{d} \times \frac{A}{2}$[/tex]
And
[tex]$C_{air}=\frac{1}{2} \frac{\epsilon_0}{d} \times \frac{A}{2}$[/tex]
In parallel combination,
[tex]$C_{eq}= C_k + C_{air}$[/tex]
[tex]$C_{eq} = \frac{1}{2} \frac{\epsilon_0 A}{d}(1+k)$[/tex]
[tex]$C_{eq} = \frac{1}{2} \times \frac{8.85 \times 10^{-12} \times 0.0010}{0.01} \times (1+3)$[/tex]
[tex]$C_{eq} = 1.77 \times 10^{-12}\ F$[/tex]
Then energy,
[tex]$U_2 =\frac{1}{2} C_{eq} V^2$[/tex]
[tex]$U_2=\frac{1}{2} \times 1.77 \times 10^{-12} \times (15V)^2$[/tex]
[tex]$U_2=1.99 \times 10^{-10} \ J$[/tex]
b). Now the charge on the [tex]\text{capacitor}[/tex] is :
[tex]$Q=C_{eq} V$[/tex]
[tex]$Q = 1.77 \times 10^{-12} \times 15 V$[/tex]
[tex]$Q = 26.55 \times 10^{-12} \ C$[/tex]
Now when the capacitor gets disconnected from battery and the [tex]\text{dielectric}[/tex] is slowly [tex]\text{removed the rest}[/tex] of the way out of the [tex]\text{capacitor}[/tex] is :
[tex]$C_3=\frac{A \epsilon_0}{d}$[/tex]
[tex]$C_3 = \frac{0.0010 \times 8.85 \times 10^{-12}}{0.01}$[/tex]
[tex]$C_3=0.885 \times 10^{-12} \ F$[/tex]
[tex]$C_3 = 0.885 \times 10^{-12} \ F$[/tex]
Without the dielectric,
[tex]$U_3=\frac{1}{2} \frac{Q^2}{C}$[/tex]
[tex]$U_3=\frac{1}{2} \times \frac{(25.55 \times 10^{-12})^2}{0.885 \times 10^{-12}}$[/tex]
[tex]$U_3=3.98 \times 10^{-10} \ J$[/tex]
You're carrying a 3.0-m-long, 24 kg pole to a construction site when you decide to stop for a rest. You place one end of the pole on a fence post and hold the other end of the pole 35 cm from its tip. How much force must you exert to keep the pole motionless in a horizontal position?
Answer:
[tex]F=133N[/tex]
Explanation:
From the question we are told that:
Length [tex]l=3.0m[/tex]
Mass [tex]m=24kg[/tex]
Distance from Tip [tex]d=35cm[/tex]
Generally, the equation for Torque Balance is mathematically given by
[tex]mg(l/2)=F(l-d)[/tex]
[tex]2*9.81(3/2)=F(3-35*10^-2)[/tex]
Therefore
[tex]F=133N[/tex]
An energy efficient light bulb uses 15 W of power for an equivalent light output of a 60 W incandescent light bulb. How much energy is saved each month by using the energy efficient light bulb instead of the incandescent light bulb for 4 hours a day? Assume that there are 30 days in one month
A. 7.2 kW⋅hr
B. 21.6 kW⋅hr
C. 1.8 kW⋅hr
D. 5.4 kW⋅hr
E. 1.35 kW⋅hr
Answer: (d)
Explanation:
Given
15 W is equivalent to 60 W light that is, it save 45 W
So, for 4 hours it is, [tex]4\times 45=180\ W.hr[/tex]
For 30 days, it becomes
[tex]\Rightarrow 180\times 30=5400\ W.hr\\\Rightarrow 5.4\ kWh[/tex]
Thus, [tex]5.4\ kWh[/tex] is saved in 30 days
option (d) is correct.
The speed of a horse is 134 meters per second how long does it takes to travel a distance of 19,311?
Answer:
just need some focus
Explanation:
tan 13. The speed of a horse is 134 meters per second how long does it take to travel a distance of 19,311m? M+ tud V 134 14. You are walking down the block and see your neighbor's pitbull 30 meters away, out of the fence, starring at you. Suddenly, he starts running towards you at 20m/s. How long will it be before you're the pitbull's lunch? V 15. A pendulum has a frequency of 2 Hz what is it's period. T = 1/2 16. You have just finished a 1600 mile trip, and it took you 16 hours. What was your average speed V = Ad At 17. You are flying from New York, NY to SanFrancisco California, a distance of 2582 miles, it takes 6.33hrs to complete the flight what was your average speed? give answer in m/s. V = Ad = At 3 of 6
5. A body falls freely from rest. It covers as much distance in the last second of its
motion as covered in the first three seconds. The body has fallen for a time of:
B) 5s
C) 7s
D) 9s
A) 35
Answer:
B 5s
Explanation:
Because of the Displacement in the nth second of the free fall is
Snth=21g(t12−t22)
Given that (tn−tn−1)=1
Displacement in 3 seconds of the free fall
S=21gt2
S=21×10×32
S=45m
Given that: Snth=45
On solving that we get:
t1=5sec
what is simple machine?
Explanation:
Those tools that helps to make our work easier ,faster and more convenient in our daily life it is called simple Machine.
Particle A has less mass than particle B. Both are pushed forward across a frictionless surface by equal forces for 1 s. Both start from rest. Which is true? A. A has more momentum. B. B has more momentum. C. A and B have the same momentum D. Not enough information.
Answer:
Both will have the same momentum.
P = M v momentum
v = a t for uniform acceleration
P = M a t
But a = F / M
P = M (F / M) t = F t so both have the same momentum
How is centripetal force affected if an object increases its speed?
A. Decreases
B. Increases
C. Cut in half
D. No effect
Answer:
B. Increases.
Explanation:
[tex]{ \bf{F = \frac{m {v}^{2} }{r} }} \\ { \bf{F \: \alpha \: {v}^{2} }}[/tex]
Keeping mass, and radius constant, speed or velocity is directly proportioanal to centripetal force.
,In order to increase the speed of an object on a circular path, YOU have to increase the centripetal force acting on it.
A mass is hanging from the end of a horizontal bar that pivots around an axis through its center, but it is being held stationary. The bar is then released and begins to rotate. As the bar rotates from horizontal to vertical, the magnitude of the torque on the bar: ________
Answer:
The torque decreases because as the hanging mass goes down, the moment arm about the pivot point decreases. Since the torque is directly proportional to the length of the moment arm, torque decreases.
The torque decreases because as the hanging mass goes down, the moment arm about the pivot point decreases. Since the torque is directly proportional to the length of the moment arm, torque decreases.
What is the difference between atomic number and atomic mass ?Atomic number of an element is defined as total number of protons present in the nucleus, neutrons carry no net electrical charge, so it is the charge number of the nucleus.
atomic mass of an element can be defined as the atomic weight is measured total mass of an element’s atom, the total number of neutrons and protons in the nucleus of an atom.
Both Atomic mass and an atomic number of elements are closely related if atomic number is high, then the atomic mass is also said to be high.
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Select the correct answer. Which of Newton's laws explains why your hands get red when you press them hard against a wall? A. Newton's law of gravity B. Newton's first law of motion C. Newton's second law of motion D. Newton's third law of motion
Answer:
D newton third law
Explanation:
good luck
A hot-air balloon plus cargo has a mass of 308 kg and a volume of 2910 m3 on a day when the outside air density is 1.22 kg/m3. The balloon is floating at a constant height of 9.14 m above the ground.
Required:
What is the density of the hot air in the balloon?
9514 1404 393
Answer:
1.114 kg/m³
Explanation:
The total mass of the air in the balloon and the balloon + cargo will be the mass of the displaced air. If d is the density of the air in the balloon, then we have ...
2910d +308 = 2910×1.22
Solving for d, we find ...
2910d = 2919(1.22) -308
d = 1.22 -308/2910
d ≈ 1.114 . . . kg/m³
The density of the hot air is about 1.114 kg/m³.
A force cannot exist without an agent and a system.
True
False
Answer:
true
Explanation:
forces require an agent
you should always be able to identify what (the agent) is producing the force
please answer all of them
I'll give brainly if answer for points will be reported
Answer:
Level 1-
1. It depends of the sense and the magnitude of the force
2. Electric force
3. A contact force need to touch to act in the object, like push a box for example. A non-contact force don't need to touch to act in the object, like an magnet attracting other magnet
4. The pressure is the force divided by the area. The unit for pressure in the international system is Pascal
5. Because the pressure is applied in all the surface of our bodies, so the force is divided by the surface area of our bodies.
Level 2-
1. The balloons stick to the walls because when she rubbed they in her clothes they earned eletric charge, and when they touched the wall, the electric charges of the wall got polarized and it creats a attraction force.
The same happened with the water stream. The balloons were charged with electric charges and the water was attracted by it.
2. Mass is the amount of matter, it's an scalar quantity. Weight is the force created by the attraction of a massive body as the Earth, and another body as a human, and a force is a vector
3. It's for increase the surface area, so the pressure will be decreased
4. When a person pulls up the syringe plunger the pressure inside the syringe is smaller than the pressure outside, so the pressure push the liquid into the syringe
5. a) The stream of the top is falling closer than the stream from the bottom, causa in the top the pressure is lower than in the bottom. In the bottom, beyond the air pressure, it has also the whole column of water making more pressure, so it goes far.
b) The streams are all near because the holes are in the same height, so the pressure is divided for all the holes.
Level 3-
1. The girl.
pressure of the girl: 50/1 = 50
pressure of the man: 100/25 = 4
pressure of the elephant: 4500/250 = 18
So, the girl exerts more pressure.
2. When the can is heated the air inside expands and get out of it. If you seal the mouth of the can, the air cannot return to inside it, and when it get colder the air inside will shrink back to the normal volume, so it will occupy less space and the outside pressure will exerts a force and deform the can.
A train starts from rest (at position zero) and moves with constant acceleration. On the first observation, its velocity is 20m/s and 80seconds later the velocity became 60m/s. At 80s calculate the position, average velocity, and the constant acceleration over the interval.(7-points)
The value of the acceleration is a = 0.5 m/s². The position at 80 s is x = 3200 m and finally the average velocity is v = 40 m/s.
Acceleration:
We can use the fallowing kinematic equation to get the acceleration at 80 s.
[tex]a=\frac{v_{f}-v_{i}}{t}[/tex]
Where:
v(i) is the initial velocity (20 m/s)v(f) is the final velocity (60 m/s)t is the interval (80 s)The, we have:
[tex]\vec{a}=\frac{60-20}{80}[/tex]
[tex]\vec{a}=0.5\: m/s^{2}[/tex]
Position:
Knowing the acceleration we can find the position using the falling equation.
[tex]\vec{x}=v_{i}t+0.5at^{2}[/tex]
[tex]\vec{x}=20*80+0.5*0.5*80^{2}[/tex]
[tex]\vec{x}=3200 m[/tex]
Average velocity:
The definition of the average velocity is:
[tex]\vec{v}=\frac{\Delta x}{t}[/tex]
[tex]\vec{v}=\frac{x_{f}-x_{i}}{t}[/tex]
[tex]\vec{v}=\frac{3200-0}{80}[/tex]
[tex]\vec{v}=40\: m/s[/tex]
Learn more about the kinematic equations here:
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I hope it helps you!
Air is compressed polytropically from 150 kPa, 5 meter cube to 800 kPa. The polytropic exponent for the process is 1.28. Determine the work per unit mass of air required for the process in kilojoules
a) 1184
b) -1184
c) 678
d) -678
Answer:
wegkwe fhkrbhefdb
Explanation:B
What is utilization of energy
Explanation:
Energy utilization focuses on technologies that can lead to new and potentially more efficient ways of using electricity in residential, commercial and industrial settings—as well as in the transportation sector
What is cubical expansivity of liquid while freezing
Answer:
"the ratio of increase in the volume of a solid per degree rise of temperature to its initial volume" -web
Explanation:
tbh up above ✅
Answer:
cubic meter
Explanation:
Increase in volume of a body on heating is referred to as volumetric expansion or cubical expansion
Both of these questions are the same but their answers in the answer key are different. Why?
8. A mass of 10 Kg is accelerating at 3 m/s2. What is the applied net force?
Answer:
Explanation:
F = ma
F = (10)(3)
F = 30 N
Answer:
[tex]\boxed {\boxed {\sf 30 \ Newtons}}[/tex]
Explanation:
We are asked to find the applied net force. According to Newton's Second of Law, force is the product of mass and acceleration.
[tex]F= m \times a[/tex]
The object has a mass of 10 kilograms and it is accelerating at 3 meters per second squared.
m= 10 kg a= 3 m/s²Substitute the known values into the formula.
[tex]F= 10 \ kg \times 3 \ m/s ^2[/tex]
Multiply.
[tex]F= 30 \ kg \times m/s^2[/tex]
1 kilogram meter per second squared is equal to 1 Newton, so our answer of 30 kg × m/s² is equal to 30 N.
[tex]F= 30 \ N[/tex]
The applied net force is 30 Newtons.
Two resistances, R1 and R2, are connected in series across a 12-V battery. The current increases by 0.500 A when R2 is removed, leaving R1 connected across the battery. However, the current increases by just 0.250 A when R1 is removed, leaving R2 connected across the battery.
(a) Find R1.
Ω
(b) Find R2.
Ω
Answer:
a) R₁ = 14.1 Ω, b) R₂ = 19.9 Ω
Explanation:
For this exercise we must use ohm's law remembering that in a series circuit the equivalent resistance is the sum of the resistances
all resistors connected
V = i (R₁ + R₂)
with R₁ connected
V = (i + 0.5) R₁
with R₂ connected
V = (i + 0.25) R₂
We have a system of three equations with three unknowns for which we can solve it
We substitute the last two equations in the first
V = i ( [tex]\frac{V}{ i+0.5} + \frac{V}{i+0.25}[/tex] )
1 = i ( [tex]\frac{1}{i+0.5} + \frac{1}{i+0.25}[/tex] )
1 = i ( [tex]\frac{i+0.5+i+0.25}{(i+0.5) \ ( i+0.25) }[/tex] ) = [tex]\frac{i^2 + 0.75i}{i^2 + 0.75 i + 0.125}[/tex]
i² + 0.75 i + 0.125 = 2i² + 0.75 i
i² - 0.125 = 0
i = √0.125
i = 0.35355 A
with the second equation we look for R1
R₁ = [tex]\frac{V}{i+0.5}[/tex]
R₁ = 12 /( 0.35355 +0.5)
R₁ = 14.1 Ω
with the third equation we look for R2
R₂ = [tex]\frac{V}{i+0.25}[/tex]
R₂ =[tex]\frac{12}{0.35355+0.25}[/tex]
R₂ = 19.9 Ω
a bullet is dropped from the same height when another bullet is fired horizontally they will hit the ground
Answer:
simultaneously
Time taken to reach the ground depends on the vertical component of velocity, not horizontal component of velocity.
A 1050 kg car accelerates from 11.3 m/s to 26.2 m/s . What impulse does the engine give?
Answer:
I = 15,645. kg*m/s or 15,645 N*s
Explanation:
I = m(^v)
I = 1050kg((26.2m/s-11.3m/s)
I = 15,645. kg*m/s
Phân biệt các đặc điểm khác nhau giữa chất rắn, chất lỏng
Answer:
şen çal kapimi turkish drama
the mass of an object is 10 kg and the velocity is 4 m/s, what is the momentum?
The answer is 40 kg. m/s.
Formula for momentum:
p=mv
p=(10 kg.)(4 m/s)
So, therefore, the final answer is p=40 kg. m/s.
I hope this helped answer your question. Enjoy your day, and take care!
Answer: its 400 n/s
Explanation:
cus my thing said it was right
A projectile is launched with speed of 128 m/s, at an angle of 60° with the horizontal. After 2.0 s, what is the vertical component of the projectile's velocity?
After 2.0s, what is the speed of the projectile?
Answer:
a) 91 m/s
b) 111 m/s
Explanation:
v = u + at
v = 128sin60 + (-9.8)(2.0) = 91.25125... m/s
v = √(vx² + vy²) = √((128cos60)² + 91.25125²) = 111.4575... m/s
