Answer:
9 kilojoules of energy are stored in a kilogram of concrete due to sensible heat.
Explanation:
In this exercise we need to determined the sensible heat store in a kilogram of concrete due to a change in temperature. Sensible heat ([tex]Q[/tex]), measured in kilojoules, is defined by the following expression:
[tex]Q = m\cdot c\cdot (T_{f}-T_{o})[/tex] (1)
Where:
[tex]m[/tex] - Mass, measured in kilograms.
[tex]c[/tex] - Average specific heat of concrete, measured in kilojoules per kilogram-degree Celsius.
[tex]T_{o}[/tex], [tex]T_{f}[/tex] - Initial and final temperatures of concrete, measured in degrees Celsius.
If we know that [tex]m = 1\,kg[/tex], [tex]c = 0.9\,\frac{kJ}{kg\cdot ^{\circ}C}[/tex], [tex]T_{o} = 20\,^{\circ}C[/tex] and [tex]T_{f} = 30\,^{\circ}C[/tex], then the energy store in a kilogram of concrete is:
[tex]Q = (1\,kg)\cdot \left(0.9\,\frac{kJ}{kg\cdot ^{\circ}C} \right)\cdot (30\,^{\circ}C-20\,^{\circ}C)[/tex]
[tex]Q = 9\,kJ[/tex]
9 kilojoules of energy are stored in a kilogram of concrete due to sensible heat.
Jennifer and katie stand and lean on each other. Jennifer weighs 150 pounds and katie weighs 120 pounds.
Answer:
Jennifer
Explanation:
she has more mass which means she is using more force
in which medium does the speed of air is the greatest? explain why?
The speed of air greatest in a medium with high pressure. Air is moving from high pressure to low pressure areas called the winds.
What are winds?The natural movement of air or other gases in relation to a planet's surface is referred to as wind. There are many different sizes of winds, ranging from thunderstorm flows that last only a few minutes to local breezes.
Large-scale atmospheric circulation is primarily brought on by the planet's rotation and the difference in temperature between the equator and the poles (Coriolis effect).
The air can move through a medium as well through vacuum. Air blows with the highest speed when the medium have higher temperature and pressure.
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Why can you see an apple as green and not red?
Answer:
A lot of Dietary Fiber.
Explanation:
Answer:
Red apples get their color from anthocyanins. These are pigments, or natural colorings, that develop as the apple grows. ... It absorbs all the colors of the rainbow—except for red. The red light reflects off the apple and our brain and eyes work together to let us know what color we are seeing.
A wrench is accidentally dropped from the top of a mast on a sailboat. Will the wrench hit at the same place on the deck whether the sailboat is at rest of moving with a constant velocity
Answer:
Yes, because the wrench is moving at the same speed as the sailboat.
The main difference is that a person on the ground would see the wrench moving diagonally, while a person on the boat would see the wrench falling straight down,
This difference in paths lead to the relativistic change in lengths.
Which is a correct description of Hooke's law?
-The force applied to a spring equals the product of the spring constant and the displacement.
-The force applied to a spring equals the spring constant divided by the displacement.
-The spring constant of a spring equals the product of the force applied and the displacement.
-the spring constant of a spring equals the displacement divided by the force applied.
Answer:
The force applied to a spring equals the product of the spring constant and the displacement.
Explanation:
From Hooke's law, the force required to extend or compress a spring by a distance is proportional to the distance. This means extension is proportional to force.
Mathematically it is stated as;
F= -k*x where k is the spring constant and x is the displacement of the spring after adjustment.
Hooke's law is an example of elasticity property of a material which is the ability of the object to return to a normal shape after experiencing a distortion also called "restoring force"
Answer:
Option A
Explanation:
The purpose of a cell phone cover is to protect your phone from impact forces. How does a cell phone case do this?
Answer:
it covers your phone so when you drop it it reduces the chance and breaking
QUESTION 2 DOK 3 A Thompson's gazelle has a maximum acceleration of 4.5 m/s2 At this acceleration, how much time is required for it to reach a speed of 40 km/h?
Answer:
2.47 s
Explanation:
Convert the final velocity to m/s.
40 km/h → 11.1111 m/sWe have the acceleration of the gazelle, 4.5 m/s².
We can assume the gazelle starts at an initial velocity of 0 m/s in order to determine how much time it requires to reach a final velocity of 11.1111 m/s.
We want to find the time t.
Find the constant acceleration equation that contains all four of these variables.
v = v₀ + atSubstitute the known values into the equation.
11.1111 = 0 + (4.5)t 11.1111 = 4.5t t = 2.469133333The Thompson's gazelle requires a time of 2.47 s to reach a speed of 40 km/h (11.1111 m/s).
Which item rotates in a magnetic field as an electric motor produces kinetic energy.
A. Lightbulb
B. Loop of wire
C. Battery
D. Permanent magnet
Answer:
Loop of Wire
Explanation:
2.Find the magnitude and direction of the resultant velocity vector for the following perpendicular velocities: a. a fish swimming at 3.0 m/s relative to the water across a river that moves at 5.0 m/s b. a surfer traveling at 1.0 m/s relative to the water across a wave that is traveling at 6.0 m/s
Answer:
a. The magnitude of the resultant velocity vector of the fish is approximately 5.83 m/s
The direction of the resultant velocity vector of the fish is approximately 30.93° relative to the direction of the river
b. The magnitude of the resultant velocity vector of the surfer is approximately 6.083 m/s
The direction of the resultant velocity vector of the surfer is approximately 9.46° relative to the direction of the wave
Explanation:
a. The given parameters of the fish and the river are;
The speed with which the fish is swimming across the river, v₁ = 3.0 m/s
The velocity with which the river is flowing, v₂ = 5.0 m/s
Therefore, in vector form, we have;
v₁ = 3.0·j
v₂ = 5.0·i
The resultant velocity, R = v₁ + v₂ = 5.0·i + 3.0·j
∴ R = 5.0·i + 3.0·j
The magnitude of the resultant velocity vector, [tex]\left | R \right |[/tex] = √(5.0² + 3.0²) =√34 ≈ 5.83
The magnitude of the resultant velocity vector, of the fish, [tex]\left | R \right |[/tex] ≈ 5.83 m/s
The direction of the resultant velocity of the fish, θ = arctan(3.0/5.0) ≈ 30.93°
Therefore, The direction of the resultant velocity vector of the fish, θ ≈ 30.93° relative to the direction of the river
b. The given parameters of the surfer and the wave are;
The speed with which the surfer is travelling, v₁ = 1.0 m/s
The speed of the wave travelling across, v₂ = 6.0 m/s
Therefore, in vector form, we have;
v₁ = 1.0·j
v₂ = 6.0·i
The resultant velocity, R = v₁ + v₂ = 1.0·i + 6.0·j
∴ R = 1.0·i + 6.0·j
The magnitude of the resultant velocity of the surfer, [tex]\left | R \right |[/tex] = √(1.0² + 6.0²) =√37 ≈ 6.083
The magnitude of the resultant velocity vector of the surfer, [tex]\left | R \right |[/tex] ≈ 6.083 m/s
The direction of the resultant velocity of the surfer, θ = arctan(1.0/6.0) ≈ 9.46°
Therefore, The direction of the resultant velocity vector of the surfer, θ ≈ 9.46° relative to the direction of the wave
A force of 90N is applied to each cart below, which one will accelerate the fastest?
Mass: 5 kg
Mass: 6 kg
mass: 8 kg
Mass: 9 kg
Answer:
5kg
Explanation:
The cart with the least amount of mass will result in the fastest acceleration.
The cart with the fastest acceleration is 5 kg cart because its mass is the smallest.
The given parameters;
applied force, F = 90 Nmass of cart: 5kg, 6kg, 8 kg, 9 kgAccording to Newton's second law of motion, the force applied to an object is directly proportional to the product of mass and acceleration of the object.
F = ma
The acceleration of the 5 kg cart is calculated as follows;
[tex]a = \frac{F}{m} \\\\a = \frac{90}{5} = 18 \ m/s^2[/tex]
The acceleration of the 6 kg cart is calculated as follows;
[tex]a = \frac{F}{m} \\\\a = \frac{90}{6} = 15 \ m/s^2[/tex]
The acceleration of the 8 kg cart is calculated as follows;
[tex]a = \frac{F}{m} \\\\a = \frac{90}{8} = 11.25 \ m/s^2[/tex]
The acceleration of the 9 kg cart is calculated as follows;
[tex]a = \frac{F}{m} \\\\a = \frac{90}{9} = 10 \ m/s^2[/tex]
Thus, the cart with the fastest acceleration is 5 kg cart because its mass is the smallest.
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A golf ball of mass m is hit by a golf club so that the ball leaves the tee with speed v. The club is in contact with the ball for time T. The average force of the club on the ball during the time T is:
Answer:
Explanation:
Given
Mass = m
Time = t
Force = mass × acceleration ..... 1
Where acceleration = velocity/time
Ave Force = m×∆v/∆t
= mv/t
Will give brainliest!! Pls answer! HELP ME!!!!!!
Answer:
See the explanation.
Explanation:
Q9. Irregular reflection happens when a set of parallel beams are reflected from non-smooth surface which results in non-parallel reflected beams.
Q10.
i) Periscope
ii) There are different types of periscopes but the main characteristic of this instrument is observation over the obstacles or in general objects that are not in the line-of-sight. Basic Periscope uses parallel angled mirrors to project objects that are above the surface in submarines.
a brown bear runs at the speed of 9.0m/s with 23,000 j of kinetic energy
Which of the following is evidence that a physical change has
occurred? *
a. Broken glass
b. Rust
c. Bubbles
d. Formation of a solid precipitate
Answer:
Broken glass
Explanation:
What happens to distance when velocity is doubled
can some one explain me big bang theory ?
Answer:
The Big Bang Theory is the leading explanation about how the universe began. At its simplest, it says the universe as we know it started with a small singularity, then inflated over the next 13.8 billion years to the cosmos that we know today.
a chuck wagon with an initial velocity of 4 m/s and a mass of 35 kg gets a push with 350 joules of force. what is the wagon's final velocity?
Answer:
the final velocity of the wagon is 6 m/s.
Explanation:
Given;
initial velocity of the wagon, u = 4 m/s
mass of the wagon, m = 35 kg
energy applied to the wagon, E = 350 J
The final velocity of the wagon is calculated as;
E = ¹/₂m(v² - u²)
[tex]m(v^2-u^2) = 2E\\\\v^2-u^2 = \frac{2E}{m} \\\\v^2 = \frac{2E}{m} + u^2\\\\v = \sqrt{\frac{2E}{m} + u^2} \\\\v = \sqrt{\frac{2(350)}{35} + (4)^2}\\\\v = 6 \ m/s[/tex]
Therefore, the final velocity of the wagon is 6 m/s.
Given:
Wagon's initial velocity,
u = 4 m/sMass,
m = 35 kgApplied energy,
E = 350 JWe know,
→ [tex]E = \frac{1}{2} m(v^2-u^2)[/tex]
→ [tex]m(v^2-u^2) = 2E[/tex]
or,
→ [tex]v^2-u^2 = \frac{2E}{m}[/tex]
→ [tex]v= \sqrt{\frac{2E}{m} +u^2}[/tex]
By substituting the values,
[tex]= \sqrt{\frac{2(350)}{35}+(4)^2 }[/tex]
[tex]= 6 m/s[/tex]
Thus the answer above is correct.
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which rock is most likely phyllite
Answer/Explanation:
Phyllite is a very common metamorphic rock, found in many parts of the world. It forms when sedimentary rocks are buried and mildly altered by the heat and directed pressure of regional metamorphism.
Answer:
metamorphic rock
Explanation:
Phyllite is a very common metamorphic rock, found in many parts of the world. It forms when sedimentary rocks are buried and mildly altered by the heat and directed pressure of regional metamorphism.
An object with mass 'm' is moving in a circle of radius 'R' at a constant speed of 'v.' The acceleration of the object will INCREASE if _____. List all that apply ... .
Answer:
Explanation:
The acceleration of an object is given by the formula
a = v²/r
The acceleration of the object is bound to increase, if and only if the following are changed as well.
The mass of the object is increased,
The speed of the object is increased,
The radius of the object is contrarily decreased
Taking another look at the formula, we see that if we increase the speed of the object, it increases the acceleration. And since the radius is in the denominator, it has to be reduced for the acceleration to increase
Why would it be incorrect to say that the bulb supplies 60 J of light energy energy each second
Answer:
Explanation:
A 60W bulb , consumes electrical energy of 60 J per second but it does not give out all the energy in the form of light . Most of the energy consumed by it is wasted in the form of heat . Only a fraction of energy is converted into light energy .
Hence, it is wrong to say that bulb supplies 60 J of light energy each second .
What effect does noise have on different types of signals?
A. It distorts digital signals, making them unreliable.
B. It distorts analog signals, making them unreliable.
C. Noise has no effect on either analog or digital signals.
D. Noise prevents the transmission of both analog and digital
signals.
Answer: it is actually B. :)
Explanation:
Noise can distort analog signals making them unreliable.
What is noise?The random or unwanted signal that mixes up with the original signal is called noise. Noise is an unwanted signal that interferes with the original message signal and causes the message signal's parameters to be corrupted. The message is transformed as a result of this change in the communication process. It's most likely to be inputted at the receiver or channel.Noise can actually bury, distort or cause interference to the analog signal carrying the intelligent information.
What is analog signal?A signal in which a characteristic grows and decreases in lockstep with the object being sent is known as analog signal. The power of the radio wave, for example, rises and falls in accordance with the loudness of the original sound in AM radio.Hence, the correct answer is B.
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A Stone thrown from the top of a building is given an initial velocity Of 20.0 metre per second straight upward determine the time in second at which the stone reaches its maximum height. ( Take sec2 g=9.8m/s)
A) 2.8
B) 2.04
C) 1.67
D) 2.7
We know that,
[tex]{\boxed{\sf{v=u+gt}}}[/tex]
[ Put values ]
[tex]\begin{gathered} \implies \sf \: {0} \: = {20} + ( - 9.8) \times t \\ \\ \implies \sf \: 0 = 20 - 9.8t \\ \\ \implies \sf \: 9.8t = 20 \\ \\ \implies \sf \: t = \dfrac{20}{9.8} \\ \\ \implies \sf \: t = 2.04\end{gathered}[/tex]
Therefore, the time at which the stone reaches its maximum height will be 2.04 s.
A cube has sides of length 10 cm and weighs 10 N.
Calculate the pressure when it rests on one side ....N/cm2
Answer:
P = r g h where r here is the density m / V and then P is the pressre.
W (weight) = m g
m = 10 N / 9.8 m / s^2 = 1.02 kg
r (density) = m / V = 1.02 kg / 1000 cm^3 = .00102 kg/cm^3
P = .00102 kg / cm3 * 9.8 m/s^2 * 10 cm
P = .1 kg m / (s^2 cm^2)
Since 1 N = kg m / s^2 then P = .1 N / cm^2
More simply P = F / A = 10 N / 100 cm^2 = .1 N / cm^2
A 60 kg swimmer suddenly dives from a 150 kg raft with a speed of 1.5 m/s. The raft is initially at
rest. What is the speed of the raft immediately after the diver jumps if the water has negligible
effect on the raft?
Answer:
v2 = 0.6 m/s in opposite direction
Explanation:
The computation of the speed of the raft is as follows
The center of system mass would be remains at the same place also it has no external force applied
Therefore
V = 0
So,
M1.V1= - (M2.V2)
where,
M1 = 60 kg, V1 = 1.5 m/s
M2 = 150 kg
Now
60 × 1.5 = - 150 × v2
v2 = -0.6 m/s
v2 = 0.6 m/s in opposite direction
Using the rules for significant figures, what do you get when you multiply 67.6 by 1.2?
Answer:
81
Explanation:
The problem here is to use the rules for significant figures in the multiplication below.
67.6 x 1.2:
This product will yield an answer that will produce the least number of significant figures.
67.6 has 3 significant figures; 6, 7 and 6
1.2 has 2 significant figures; 1 and 2
The product must give us an answer of two significant figures:
67.6 x 1.2 = 81.12 to 2significant figures gives 81
The solution to this problem is 81
Earth travels fastest in January and slowest in July. What is the most likely explanation for this?
A. Earth is nearest the Sun in July and farthest away in January.
B. Earth is nearest the Sun in January and farthest away in July.
C. Earth is nearest the Sun in April and farthest away in October.
D. Earth is nearest the Sun in October and farthest away in April.
Answer:
Earth is nearest the Sun in July and farthest away in July.
Explanation:
Answer:
Correct Answer: B.
Explanation:
Earth is nearest the Sun in January and farthest away in July. Explanation: According to Kepler's Second Law, a planet travels fastest when it is nearest its sun. This means that Earth is actually closest to the Sun in January, when it is winter in the northern hemisphere!
how temperature, surface tension and the diameter of the tube affect capillary action.
The surface tension acts to hold the surface intact. Capillary action occurs when the adhesion to the surface material is stronger than the cohesive forces between the water molecules. ... Water wants to stick to the glass and surface tension will push the water up, until the force of gravity prevents further rise.
Narrower tube openings allow capillary action to pull water higher
A hydrogen atom is isolated in a vacuum chamber, the electron is now separated from the proton and moved to a distance 1 cm away. Let Fg be the magnitude of the gravitational force between the proton and electron, and let Fe be the magnitude of the electric force between the proton and electron. How does the ratio Fg/Fe change as the particles are separated
Answer:
hello your question is incomplete attached below is the complete question
answer: Fg / Fe does not change ; it is the same nonzero value for all separations ( A )
Explanation:
Given that distance between proton and electron is 1 cm
Fg = Gm1m2 / r^2
where :
G ( gravitational constant )= 6.67 * 10^-11 Nm^2 / kg^2
m1 ( mass of proton ) = 1.67 * 10^-27 kg
m2 ( mass of electron ) = 9.11 * 10^-31 kg
Electrical force
Fe = kq1q2 / r^2
k = 9*10^9
hence ;
Fg / Fe = (Gm1m2 / r^2) / (kq1q2 / r^2 )
= Gm1m2 / kq1q2
The purpose of a cell phone cover is to protect your phone from impact forces. How does a cell phone case do this?
Answer:
the material of the phone case
The purpose of a cell phone cover is to protect your phone from impact forces. It is done by absorbing the impact of force by back cover.
What is Force ?
Force is responsible for the motion of an object. it produces acceleration in the body. According to newton's second law force is mass times acceleration i.e. F =ma. Its SI unit is N which is equivalent to kg.m/s².
The case is made in such a way that, if the cell phone is dropped, the cover will absorb the kinetic energy of the falling phone by the means of deforming without transferring the impact onto the phone.
Cell phone cover is made up of rubber which can restore the forces like a spring. when u apply force to the rubber it get displaced and applied force is stored in the rubber. when cell phone drops, rubber of the cover absorbs the energy of impact. it also provides shied protection to the phone.
Hence this is how cell phone case do this.
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A force of 100.0N accelerates a 5.0 kg box at 15.0 m/s^2 along a level surface. Find the coefficient of sliding friction for the box. After that, how far will the box have gone after 5.0 seconds of pulling it?
By balancing the force, we get :
100 - Frictional Force = ma
100 - μmg = ma
100 - μ(5)(10) = (5)(15)
50μ = 25
μ = 0.5
Distance travelled by box in 5 seconds is :
[tex]d = ut + \dfrac{at^2}{2}\\\\d = 0 + \dfrac{15\times 5^2}{2}\\\\d = 187.5\ m[/tex]
Hence, this is the required solution.