Answer:
A
Explanation:
A 15 kg box is sliding down an incline of 35 degrees. The incline has a coefficient of friction of 0.25. If the box starts at rest, how fast is it moving after it travels 3 meters?
The box has 3 forces acting on it:
• its own weight (magnitude w, pointing downward)
• the normal force of the incline on the box (mag. n, pointing upward perpendicular to the incline)
• friction (mag. f, opposing the box's slide down the incline and parallel to the incline)
Decompose each force into components acting parallel or perpendicular to the incline. (Consult the attached free body diagram.) The normal and friction forces are ready to be used, so that just leaves the weight. If we take the direction in which the box is sliding to be the positive parallel direction, then by Newton's second law, we have
• net parallel force:
∑ F = -f + w sin(35°) = m a
• net perpendicular force:
∑ F = n - w cos(35°) = 0
Solve the net perpendicular force equation for the normal force:
n = w cos(35°)
n = (15 kg) (9.8 m/s²) cos(35°)
n ≈ 120 N
Solve for the mag. of friction:
f = µ n
f = 0.25 (120 N)
f ≈ 30 N
Solve the net parallel force equation for the acceleration:
-30 N + (15 kg) (9.8 m/s²) sin(35°) = (15 kg) a
a ≈ (54.3157 N) / (15 kg)
a ≈ 3.6 m/s²
Now solve for the block's speed v given that it starts at rest, with v₀ = 0, and slides down the incline a distance of ∆x = 3 m:
v² - v₀² = 2 a ∆x
v² = 2 (3.6 m/s²) (3 m)
v = √(21.7263 m²/s²)
v ≈ 4.7 m/s
A 4812 kg boulder sits on top of a 203 m cliff. What is its PE?
Answer:
9572992.8 JExplanation:
The potential energy of a body can be found by using the formula
PE = mgh
where
m is the mass
h is the height
g is the acceleration due to gravity which is 9.8 m/s²
From the question we have
PE = 4812 × 9.8 × 203
We have the final answer as
9572992.8 JHope this helps you
the fall of a body on the earth's surface cannot be a complete free fall why ?
Explanation:
because the boy has larger surface area due to which he offers the larger air resistance which decreases the acceleration so, he will fall towards the earth's surface approximately with constant velocity.
Explain why the total positive charge in every atom of an element is always the
same.
Answer:
When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.
Explanation:
An atom has an equal quantity of positive and negative electric charges (the protons and electrons) when its electron and proton counts are equal (the protons). Since the atom has a total electric charge of zero, it is referred regarded as being neutral.
What is an atom?The atom is the smallest unit of matter that may be divided without resulting in electrically charged particles. Additionally, it is the tiniest substance with features like chemical elements. The atom is therefore the basic building block of chemistry.
Examine different electron arrangements in the electron shells that surround an atom's nucleus.
Examine different electron arrangements in the electron shells that surround an atom's nucleus. The rest is made up of a cloud of negatively charged electrons surrounding a positively charged nucleus made up of protons and neutrons. Compared to electrons, which are the lightest charged particles in nature, the nucleus is small and dense.
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A psychologist wants to identify how the holiday season impacts the anxiety levels of Americans. She wants to get results on the feelings of anxiety from over one million Americans in the next month. What design should she use and why?
Answer: survey
Explanation:
A survey can be an interview or a questionnaire which is given to a particular group in order to know their characteristics or opinions, towards certain issues.
Since the psychologist wants to get results on the feelings of anxiety from over one million Americans in the next month, the survey should be used.
An NFL wide receiver prospect runs 40 m in 4.5 seconds. What is the average speed of the wide receiver (m/s)?
Answer:
8.89 m/s
Explanation:
rate = distance/time
40m/4.5 sec = 8.8888889 m/s
When food is digested, the
smell changes considerably.
What would you call this type
of change?
A. A physical change
B. A chemical change
C. A solution change
Answer:
Chemical change
Explanation:
A chemical change is what happens. The food digested changes smell due to some enzyme the has acted on the food which catalyzes the rate of digestion. The enzymes acts on the food in order to speed up the rate of the reaction (digestion) and in turn causing the smell.
Which of the following is NOT one of the essential components of an exercise program?
Answer:
i dont know dude but ask someone who is in your grade lol
Explanation:
what is a zippper
awsedrftvgbhnjmk,l
Answer:
a jacket closing mechanism a most useful tool to preserve and protect.
Explanation:
Answer:
zip·per
/ˈzipər/
noun
a device consisting of two flexible strips of metal or plastic with interlocking projections closed or opened by pulling a slide along them, used to fasten garments, bags, and other items.
What is the cause of any sound wave?
Answer:
When an object vibrates, it causes movement in surrounding air molecules. These molecules bump into the molecules close to them, causing them to vibrate as well. This makes them bump into more nearby air molecules. This “chain reaction” movement, called sound waves, keeps going until the molecules run out of energy.
Explanation:
The image shows Earth’s orbit around the Sun.
An illustration with a circle representing the sun and a smaller circle representing a planet. The sun is at a focus of a draw ellipse that the planet is on. There are lines drawn radially out from the Sun to the elliptical path of the planet. The planet is at the part of the ellipse that is closest to the sun. The position of the planet is labeled W and the position opposite the planet is labeled X.
Which describes the changes in Earth’s motion?
The speed increases from W to X because a component of the gravitational force acts in the direction opposite to the velocity.
The speed increases from W to X because a component of the gravitational force acts in the direction of the velocity.
The speed increases from X to W because a component of the gravitational force acts in the direction opposite to the velocity.
The speed increases from X to W because a component of the gravitational force acts in the direction of the velocity.
(last choice)
The speed increases from X to W because a component of the gravitational force acts in the direction of the velocity.
D)The speed increases from X to W because a component of the gravitational force acts in the direction of the velocity.
Does gravitational force increase with distance?The gravitational force is inversely proportional to the square of the separation distance between the 2 interacting gadgets, extra separation distance will result in weaker gravitational forces. so as items are separated from every other, the pressure of gravitational attraction between them also decreases.
The force of gravity relies immediately upon the masses of the 2 gadgets, and inversely on the square of the gap between them. this means that the pressure of gravity will increase with mass, but decreases with growing distance among items.
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A steel rod has a diameter of 3.75cm.Express it's diameter in millimeters and meter
Answer:
3.75cm into millimetres
= 3.75 * 10
37.5 millimetres
3.75 cm into metres
3.75/100
= 0.0375m
A car traveled 885mi from El Paso, TX to Dallas, TX in 12.5 hours. What was the car's average speed?
Answer:
The car's average speed is 70.8 mph
Explanation:
The given parameters are;
The total distance traveled = 885 miles
The time of travel = 12.5 hours
The average speed is given by the following equation;
[tex]Average \ speed = \dfrac{Total \ Distance \ traveled}{Total \ time \ taken \ to \ travel \ the \ distance}[/tex]
Therefore, we have;
[tex]Average \ speed = \dfrac{885 \ miles}{12.5 \ hours} = 70.8 \ miles \ per \ hour[/tex]
Therefore, the car's average speed = 70.8 mph.
Answer:
The car's average speed is 70.8 mph
Explanation:
a body attains its maximum height at H . it covers 3H÷4 height at time T . then how much time will it take to cover remaining H÷4
Answer:
The time it takes the body to cover the remaining H/4 is T
Explanation:
The maximum height attained by the body = H
The time it takes the body to reach 3/4×H = T
From the kinematic equation, h = u·t - 1/2·g·t², we have;
u = 0 m/s at for the object returning back down at maximum height, therefore at the maximum height, we have;
H = u × 0 + 1/2·g·t²
H = 1/2·g·t²
t = √(2·H/g)
When h = 3/4×(H) from below, we have;
h = H/4 from above, which gives;
[tex]t_{H/4}[/tex] = √(2·H/4/g) = √(H/(2·g)) = 1/2 × √(2·H/g)
∴ The time it takes the body to cover H/4 height, while falling from above [tex]t_{H/4}[/tex] = 1/2 × √(2·H/g)
The time, [tex]t_{3 \times H/4}[/tex], it takes to cover the remaining 3/4×(H) while falling from above is [tex]t_{3 \times H/4}[/tex] = T = t - 1/2 × √(2·H/g) = √(2·H/g) - 1/2 × √(2·H/g) = 1/2 × √(2·H/g)
∴ T = 1/2 × √(2·H/g)
Therefore, the time it takes the body to reach a height of 3/4H = The time it takes the body to cover the remaining H/4 = T.
Describe how different types of motion are represented by distance-time graphs and velocity-time graphs.
Answer:
non-accelerated movement
velocity versus time a horizontal straight line.
distance versus time gives a horizontal straight line.
accelerated motion
graph of velocity versus time s an inclined line and the slope
graph of distance versus time is a parabola of the form
Explanation:
In kinematics there are two types of steely and non-accelerated movements
In a the velocity of the body is constant therefore a speed hook against time gives a horizontal straight line.
A graph of distance versus time is a straight line whose slope is the velocity of the body
x = v t
In an accelerated motion the velocity changes linearly with time, so a graph of velocity versus time is an inclined line and the slope is the value of the acceleration of the body
v = v₀ + a t
A graph of distance versus time is a parabola of the form
x =v₀ t + ½ a t²
what does a plant need to take in from environment to live?
nitrogen gas
argon
carbon dioxide
oxygen
Answer:
Carbon Dioxide.
Explanation:
Which disadvantage of nuclear power use poses the greatest threat to the environment?
the emission of greenhouse gases
the proliferation of nuclear materials
the storage and management of radioactive wastes
the high cost of building facilities
The correct answer is The storage and management of radioactive wastes
Explanation:
In general, nuclear reactions (changes in the nucleus of an atom such as fission) release a lot of energy including a lot of heat. Moreover, this heat is used by humans to obtain electricity and other types of energy, which is known as a nuclear power. This type of power is considered positive because it does not emit carbon and it is quite efficient.
However, in most cases, it is a threat to the environment and living beings because storing and managing the wastes of this type of power is difficult and expensive. Indeed, dealing with the wastes of nuclear power requires complex infrastructure, and any accident or leaking leads to serious consequences from the death of those exposed to the wastes to permanent loss of diversity or changes in nearby areas.
Answer:
C. The storage and management of radioactive wastes
Explanation:
solvent that can be used to remove ink from clothes and cleaning greasy
hands
Answer:
Rubbing Alcohol
Explanation:
What is the average depth of the oceanic crust? What percentage of our planet does it cover?
Answer: Oceanic crust, the outermost layer of Earth's lithosphere that is found under ... Sort out the facts and see how deep your knowledge goes in this quiz of the world's oceans. ... They commonly are thin (only about 10 cm [4 inches] thick) and cover a ... km (85 square miles) of seafloor to an average depth of 70 metres (230 feet).
Explanation:
A 48 N force accelerates a block at 6 m/s/s. What is the mass of the block?
Answer:8
Explanation:
m=f/a
48/6=8
The external stimulus (what causes the stress) NEED HELP ASAP
Answer:
Some examples of external stressors include:
Major life changes. These changes can be positive, such as a new marriage, a planned pregnancy, a promotion or a new house. ...
Environment. The input from the world around us can be a source of stress. ...
Unpredictable events.
Workplace.
Social.
Explanation:
You and your little sister go to the park in cheetah started to go down the plastic slide. On her way down to euros out ouch! When you rush over to ask her what happened she replied the slide shocked me. Explain why this event took place using the distribution of charges.
Why is it colder in winter than summer? Give two reasons.
Answer:
Actually, the sun goes a bit down, like it's not all the way up as to summer. How I know is that you actually can go online maybe search for some videos and see proof, I don't really know how to explain it.
Explanation:
Reason #1: If you check, go out for 12 hours and see, I think the sun is a little down.
Reason #2:
The earth’s axis is tilted.
From a Brainly user of this question for more info:
The Earth is NOT farther away from the sun in USA Winter, and NOT closer to the sun in USA Summer. In 2021, we will be NEAREST to the sun on January 2, and FARTHEST from the sun on July 5 !
NEAREST to the sun next Saturday.
FARTHEST from the sun next July 5.
** 8. How many atoms of Carbon are in C2H40?
Answer:
2
Explanation:
A huge enormous gigantic number ... two in every molecule of the stuff !
what is the wavelength of a wave with a frequency of 262 hz and a speed of 343 m/s
A. 89,8666 m/s
B. 0.76 m
C. 1.11 x 10^ -5 m
D. 1.3 m
Heya!!
For calculate wavelength, lets applicate formula:
[tex]\boxed{\lambda = V/f}[/tex]
Δ Being Δ
f = Frequency = 262 Hz
v = Velocity = 343 m/s
[tex]\lambda[/tex] = Wavelenght = ?
⇒ Let's replace according the formula:
[tex]\boxed{\lambda = 343\ m/s / 262\ Hz }[/tex]
⇒ Resolving
[tex]\boxed{\lambda = 1,3 \ m}[/tex]
Result:
The wavelength is 1,3 meters.
Good Luck!!
Answer:
D) 1.3 m
Explanation:
Have a amazing day
a force that pushes a small mass will have _ effect on the acceleration than that same force pushing on na large mass
A. greater
B. smaller
C. same
Answer:
a
Explanation:an example An astronaut in space has the same mass as he does on earth while having different ... Newton's Second Law of Motion: Force = mass x acceleration ... Push less to move it (use less force.) ... Gravity has an effect on an object in the vertical direction only.
Answer:
it is a greater
Explanation:
hope it helps
If your friend pushes a lawnmower four times as far as you do while exerting only half the force, which one of you does more work
Answer:
Him
Explanation:
He will push less but more and he will use more energy
help plz i need itttttttttttttt
Answer:
The answer is A or B. Sorry if incorrect. Hope this helps. :)
a spy satellite of mass of 1000 kg is orbiting the earth at an altitude of 300 km/s
a) what is its period
b) what is its orbital speed
Answer:
a) The period of the satellite is approximately 5,425.305 seconds (1.507 hours)
b) The orbital velocity of the satellite is approximately 7,725.8565 m/s
Explanation:
The given parameters are;
The mass of the satellite, m = 1,000 kg
The altitude at which the satellite is orbiting, h = 300 km
a) The period of the satellite is given as follows;
[tex]T = 2 \times \pi \times \sqrt{\dfrac{(R + h)^3}{g \times R^2} }[/tex]
Where;
R = The radius of the Earth = 6.371 × 10⁶ m
g = The acceleration due to gravity = 9.81 m/s²
h = The altitude of the orbit of the satellite = 300 km = 300,000 m
By substitution, we have;
[tex]T = 2 \times \pi \times \sqrt{\dfrac{((6.371 + 0.3)\times 10^6)^3}{9.81 \times (6.371 \times 10^6)^2} } \approx 5,425.305[/tex]
T ≈ 5,425.305 seconds ≈ 1.507 hours
b) The orbital velocity of the satellite is given as follows;
[tex]v_0 = \sqrt{\dfrac{G \times M_{central}}{R + h} } = \sqrt{\dfrac{g \times R^2}{R + h} }[/tex]
Where;
v₀ = The orbital velocity of the satellite
Which by substitution gives;
[tex]v_0 = \sqrt{\dfrac{9.81 \times (6.371 \times 10^6)^2}{(6.371 + 0.3) \times 10^6} } = 7,725.8565[/tex]
The orbital velocity, v₀ = 7,725.8565 m/s.
A girl whose weight is 220-N hangs from
the middle of a bar supported by four vertical
strands of rope. What is the tension in each
strand?
Answer: 55n
Explanation: