Answer:
A. 20 N down
Explanation:
It's asking how much force of gravity is acting on it. The book weighs 20 Newtons so that's how much gravity is being applied. Hope this helps
When a book that weighs 20 N sits on a table. then the force of gravity from the Earth acts on the book would be 20 N down, therefore the correct option is A.
What is gravity?It can be defined as the force by which a body attracts another body towards its center as the result of the gravitational pull of one body and another, The gravity varies according to the mass and size of the body for example the force of gravity on the moon is the 1/6th times of the force of gravity on the earth.
When an object is thrown straight up in the absence of air resistance there is no external force acting on it except the gravitational force of the earth which very much reflects the fact that the acceleration due to gravity is constant and is the result of the gravitational pull of the earth which act on the downward direction.
A book that weighs 20 N sits on a table and faces a downward force of 20N acts on the book because the force of gravity from the Earth acts on the book.
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the basic units involved in netwon?
Answer:
kilogram metre per second square
Help science 70 points
first. this is only worth 38 points second it's B
Answer:
Explanation:
Which statement best describes Cleo's mistake? Light travels through air and water in angled, scattered paths. Light does not change direction when it moves from air into water. Light slows down when it moves from air into water. Light bends away from the normal when it moves from air into water.
The question (obtained from the internet);
Cleo stated that light travels through air in straight paths, and when it moves from air to water, light changes direction, speeds up, and bends towards the normal
Answer:
The statement that best describes Cleo's mistake is;
Light slows down when it moves from air into water
Explanation:
The question;
Cleo stated that light travels through air in straight paths, and when it moves from air to water, light changes direction, speeds up, and bends towards the normal
The speed of light in water = 225,000 km/s
The speed of light in air = 299,702,547 m/s
The speed of light in vacuum = 299,792,458 m/s
Therefore, light slows down when it moves from a less dense medium to a denser medium
Light moves closer (bends) towards the normal when it moves from air into water. Light therefore, changes direction, and light moves in straight path which is known as rectilinear motion
Therefore, the statement that describes Cleo's mistake is that light actually slows down when it moves from air into water.
A bus contains a 1500 kg flywheel (a disk that has a 0.600 m radius) and has a total mass of 10,000 kg.
(a) Calculate the angular velocity the flywheel must have to contain enough energy to take the bus from rest to a speed of 20.0 m/s, assuming 90.0% of the rotational kinetic energy can be transformed into translational energy.
(b) How high a hill can the bus climb with this stored energy and still have a speed of 3.00 m/s at the top of the hill? Explicitly show how you follow the steps in the Problem-Solving Strategy for Rotational Energy.
Answer:
Explanation:
moment of inertia of flywheel = 1/2 m R²
= .5 x 1500 x .6²
= 270 kg m²
If required angular velocity be ω
rotational kinetic energy = 1/2 I ω²
= .5 x 270 x ω² = 135 ω²
kinetic energy of bus when its velocity is 20 m/s
= 1/2 x 10000 x 20²
= 2000000 J
Given 90 % of rotational kinetic energy is converted into bus's kinetic energy
135 ω² x 0.9 = 2000000 J
ω²=16461
ω = 128.3 radian /s
b )
Let the height required be h .
Total energy of bus at the top of hill = mgh + 1/2 m v²
m ( gh + .5 v²)
= 10000 ( 9.8h + .5 x 3²)
From conservation of mechanical energy theorem
10000 ( 9.8h + .5 x 3²) = 2000000
9.8h + .5 x 3² = 200
9.8h = 195.5
h = 19.95 m .
A piece of stone weigh 90 grams. When it lowered in measuring cylinder containing water. The final volume of water is 30 cubic centimetres. Calculate the density of the stone.
Answer:
3 gm / cm^3
Explanation:
Density = weight / volume
90 / 30 = 3 gm/cm^3
Please someone help me. I don't know how to do this and it's due tonight.
Answer:
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Which statement describes the energy transformation that occurs when a person eats a sandwich to gain energy for a long hike?
A. Electrical energy stored in the molecules of the sandwich is transformed into chemical energy.
B. Kinetic energy stored in the bonds of the molecules of the sandwich is transformed into chemical energy.
C. Thermal energy stored in the molecules of the sandwich is transformed into kinetic energy.
D. Chemical energy stored in the bonds of the molecules of the sandwich is transformed into kinetic energy.
D. Chemical energy stored in the bonds of the molecules of the sandwich is transformed into kinetic energy. This statement describes the energy transformation that occurs when a person eats a sandwich to gain energy for a long hike
What is Law of energy conservation ?
Law of energy conservation states that energy can neither be created nor be destroyed and can only transform from one form to other form.
From Law of energy conservation we can say that Digestion starts from that very point when we put food in our mouth so the moment you eat the sandwich, it starts getting digested and when it reaches the stomach ,your body converts its chemical energy into the movement of your muscles.
hence , correct option is :
D. Chemical energy stored in the bonds of the molecules of the sandwich is transformed into kinetic energy.
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5. If a spring with a 40 N/m spring constant is used to push a 10 kg ball to a speed of 2 m/s,
how much must the spring have been compressed assuming no energy is lost?
By compressing the spring a distance x (in m), you are storing 1/2 k x ² (in J) of potential energy, which is converted completely into kinetic energy 1/2 m v ², where
• k = 40 N/m = spring constant
• m = 10 kg = mass of the ball
• v = 2 m/s = ball's speed (at the moment the spring returns to its equilibrium point)
So we have
1/2 k x ² = 1/2 m v ²
x = √(m/k v ²) = √((10 kg) / (40 N/m) (2 m/s)²) = 1 m
Which of the following wave on the electromagnetic spectrum has more energy? Ultraviolet or x-rays?
Answer: ultraviolet
Explanation:
List five objects in your daily life that produce sounds with a high pitch and five that produce sounds with a low pitch.
Answer:
Explanation:
High pitch:
-birds chirping
-nails on a chalkboard
-flies buzzing
-children squealing
-whistle
Low pitch:
-thunder
-dogs barking
- earthquakes
- bass drum,
-cannon shot,
5 example of high pitch sound
baby crying , whistle , school bell , fire alarm , chirping of birds
5 example of low pitch sound
thunder , drum , earthquake , generator , animal roar
What is a pitch ?
It is the effect or sensation produce in brain due to sound of some particular frequency
5 example of high pitch sound
baby crying , whistle , school bell , fire alarm , chirping of birds
5 example of low pitch sound
thunder , drum , earthquake , generator , animal roar
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based on the magnetic field lines shown what is the orientation of the mystery magnet ?
Which is a leading theory for the formation of fossil fuels?
Answer:
The most widely accepted theory for the formation of fossil fuel is that fossil fuel was formed over time from decaying organic matter. Organisms died and were buried in the ground millions of years ago.
Explanation:
g00gle answer! so change it up a little :P
hope this helps :)
Using the information provided in the table, which statement BEST describes the object's motion?
Answer:
the velocity is decreasing therefore acceleration is negative
How many free electrons are there in 2.55 cm^ ^ 3 of pure Silicon Note N = Vp and rho = 1.54 free electrons / cm ^3
A: 3.93 x 10^20 free electrons
B: 6.32 x 10^20 free electrons
C: 3.93 x 10^22 free electrons
D: 6.32 x 10^2× free electrons
Answer:
C: 3.93 x 10^22 free electrons
Explanation:
The no. of free electrons can be found out using the following formula:
[tex]N = V\rho\\[/tex]
where,
N = No. of free electrons = ?
V = Volume = 2.55 cm³
ρ = density of electrons = 1.54 x 10²² free electrons/cm³
Therefore, using these values in the equation, we get:
[tex]N = (2.55\ cm^3)(1.54\ x\ 10^{22}\ free\ electrons/cm^3)\\[/tex]
N = 3.93 x 10²² free electrons
Therefore, the correct option is:
C: 3.93 x 10^22 free electrons
Mainly need help with part A. No links, thanks!
Answer:
R = 4Ω
Explanation:
If we have two resistors with resistances R1 and R2 in series the total resistance is R = R1 + R2
If the resistances are in parallel, the total resistance is given by:
1/R = 1/R1 + 1/R2.
First, we have a resistor with R1 = 1.5Ω
This resistor is connected in series with a parallel part (let's find the resistance of this parallel part), in one branch we have two resistors in series with resistances:
R2 = 8Ω and R3 = 4Ω
Because these are in series, the resistance of that branch is:
R = 8Ω + 4Ω = 12Ω
In the other branch, we have a single resistor of R4 = 4Ω
The resistance of the parallel part is:
1/R = 1/12Ω + 1/4Ω = 1/12Ω + 3/12Ω = 4/12Ω = 1/3Ω
1/R = 1/3Ω
R = 3Ω
Then we have a resistor (the first one, R1 = 1.5Ω) in series with a resistor of 3Ω.
Then the total resistance is:
R = 1Ω + 3Ω = 4Ω
Tammy is a forensic investigator examining a body at a crime scene. She notes that the body is stiff but still flexible. What does she know about the time of death?
Answer:
It happened less than 8 hours ago.
Explanation:
Over the first eight hours, the body begins to stiffen but is still flexible.
A tank of water is 4m deep. How deep does it appear when seen normally?
Answer:
The tank appears to be 3 m deep only. Step by step solution by experts to help you in doubt clearance & scoring excellent marks in exams.
How is it possible a plant can sustain itself for 70 years locked inside a jar ?
Answer:
If you are talking about the experiment in which mouse and plants are kept in a closed glass jar in sunlight so in that case, they both survive because the CO2 released by the respiration of mouse is being utilized by the plants and fixed ( phosynthesis) and O2 is released as by product, which is taken by the mouse for respiration.
a.
[tex]x + y = 0 \\ y = {x}^{2} + 2xy[/tex]
can any one tell this answer with dafination and all steps
Answer:
The system has two solutions:
(1, -1) and (0, 0)
Explanation:
We have the system of equations:
x + y = 0
x = x^2 + 2*x*y
To solve this, the first step is to isolate one of the variables in one of the equations, I will isolate x on the first one.
x = -y
Now we can replace this on the other equation, to get:
x = x^2 + 2*x*y
(-y) = (-y)^2 + 2*(-y)*y
Now we can solve this equation for y.
-y = y^2 - 2*y^2
-y = -y^2
y^2 - y = 0
We can solve this using the Bhaskara's formula:
The solutions are then:
[tex]y = \frac{-(-1) \pm \sqrt{(-1)^2 - 4*1*0} }{2*1} = \frac{1 \pm 1}{2}[/tex]
Then the two possible solutions are:
y = (1 + 1)/2 = 1
and
y = (1 - 1)/2 = 0
Suppose that we take the first one, y = 1.
Then the solution for x is given by "x = -y"
Then:
x = -1
This means that one solution of the system is (-1, 1)
If we take the other solution for y, y = 0
The value of x will be:
x = -y = -0 = 0
Then another solution of the system is (0, 0)
can em waves travel at the speed of light?
true or false
Answer:
f nothing can move faster than spped of light.
Explanation:
wheel and excel has co-axial cylinder. true or false
Answer:
True, wheel and excel has co-axial cylinder. true or false.
You can follow me to get more answer.
Answer:
true
Explanation:
yes they have two com xial cylinder and they work together
what is nylon?
answer
Answer:
Nylon is a generic designation for a family of synthetic polymers composed of polyamides.
Explanation:
A polythene rod may be charged by rubbing it with a cloth while being held in the hand but a metal rod cannot be charged in a similar way. Explain why
Answer:
Explanation:
This is because polythene rod is an insulator , therefore when it is rubbed with a cloth , electrons move easily therefore making it charged but
Metal rod is a conductor, it conduct heat . Therefore, their atoms have electrons that is constantly in motion. Therefore rubbing it with a cloth will make any difference in making it charged because it have very huge number of stable electrons which will not allow more electrons to move through them.
What is the Average Depth of the ocean?
Answer:
The average depth of the ocean is about 12,100 feet.
Explanation:
A child drops a bouncy ball. Each time it bounces, it reaches a lower height until it eventually
stops. Describe the energy transfers and explain why the ball lowered in height
Answer:
the ball's was lowered because of the gravitational force and because of the friction force's
Which one of the following statements is true: The reactive power is the power dissipated in the form of heat by the network. The reactive power is the power delivered to a load without considering the effects of the power-factor angle of the load. The apparent power is the power delivered to a load without considering the effects of the power-factor angle of the load. The real power is the power associated with reactive elements that provides a measure of the energy associated with setting up the magnetic and electric fields.
Answer:
The apparent power is the power delivered to a load without considering the effects of the power-factor angle of the load
Explanation:
If I and V are the current and voltage across the load, the apparent power, = IV
Since,
apparent power = active power + reactive power
active power = IVcosФ
reactive power = IVsinФ
So, IV = IVcosФ + IVsinФ
where I = current, V = voltage and Ф = power factor angle.
We see that the apparent power is the product of the current, I and the Voltage, V without considering the power factor angle of the load.
So, the apparent power is the power delivered to a load without considering the effects of the power-factor angle of the load.
A) write the name of any two instrument based on atmoshpheric pressure.
B)Which chemical is used to increase the setting period of cement?
C)What are the near point and far point of normal eye?
Answer:
Explanation:(a)Mercury Barometer and Aneroid Barometer
(b)Gypsum
(c)Near point of human eye is 25 cm and the far point is infinity.
A DVD spins with a period of 0.016 seconds. With what frequency is the DVD
spinning?
Answer:
It spins on the side where it looks shiny.
Explanation:
Answer:
9120-25600 RPM mate
Explanation:
I know your thinking it's crazy because of the other answer. but don't worry i looked it up for ya.
Matter cant be created or destroyed
true
false
Answer: True
no matter can be created nor destroyed in any process. if something is burned, made in a compound or anything like that all matter is still the same amount from beginning to end.
Explanation:
Please help, I’m being timed! I will give brainliest!!!!!!!
Answer:
The Answer is gonna be A. It will speed up
Explanation :if it has the same velocity it will only change if the weight is less
This is the Answer
I hope I helped
I hope you are having a great day :3:3:3:3:3:3
Answer:
B
Explanation:
Why would it speed up if it is the same velocity??
It would stay at teh same speed. It would only increase if it weighed less.