A 8,000 kg amazon truck carrying a 3000 kg package is moving at 20 m/s along a level road as shown to the left. The driver applies the brakes to slow down. The truck travels 50 meters while applying the brakes for 3.0 seconds. The package does not slide on the back of the truck. a) Calculate the rate of acceleration b) Calculate the minimum coefficient of friction between packages and the truck
Answer:
(a) -6.67 [tex]m/s^2[/tex]
(b) 0.68
Explanation:
Given that the mass of the truck, [tex]m_1=8000[/tex] kg.
Mass of the package, [tex]m_2=3000[/tex] kg.
As the package does not slide, so the acceleration of both, truck as well as the package, is the same.
Let [tex]a\;\; m/s^2[/tex] is the acceleration of the combined mass, m.
[tex]m=m_1+m_2= 8000+3000=11000[/tex] kg.
The initial velocity of the combined mass, u= 20 m/s.
Time required to stop, t=3 seconds.
Final velocity, v=0.
Displacement traveled, s=50 m.
(a) As [tex]a=\frac {v-u}{t}[/tex]
[tex]\Rightarrow a=\frac{0-20}{3}=-\frac{20}{3} =6.67 m/s^2[/tex]
Hence the acceleration of the truck is [tex]-6.67 m/s^2.[/tex]
(b) Now, [tex]a=-6.67 m/s^2[/tex] is the acceleration of the package, this acceleration is due the frictional force, f.
Due to inertia, on application of break, the package have tendency to slide to left (in the direction of velocity). But the package does not slides, this is only due to the frictional force, f, which acts in the right direction ( opposite to the direction of velocity).
So, the magnitude of frictional force required on [tex]m_2[/tex] to avoid slide is
[tex]f=|m_2a|=\frac{20}{3}m_2\times(i)[/tex]
Now, let \mu be the minimum coefficient of the friction, so
The force due to friction, [tex]f_r= \mu N[/tex],
where [tex]\mu N[/tex] is the normal reaction.
[tex]N=m_2g[/tex], where g is the acceleration due to gravity.
So, [tex]f_r=\mu m_2g\cdots(ii)[/tex]
To avoid slide, [tex]f_r\geq f[/tex]
[tex]\Rightarrow \mu m_2g\geq\frac{20}{3}m_2[/tex] [from (i)and (ii)]
[tex]\Rightarrow \mu\geq \frac{20}{3\times 9.81}[/tex] [tex][ as \;g=9.81 m/s^2][/tex]
[tex]\Rightarrow \mu \geq 0.68[/tex]
Hence, the minimum value of coefficient of friction between packages and the truck os 0.68.
A group of students conduct an experiment with a block of wood sliding down an incline. They find that the final energy of the block is less than the initial energy of the block. Which statement best describes this situation?(1 point)
The students made an error in calculating the initial energy.
Some energy was transformed to other forms.
Some energy was destroyed or lost.
The students made an error in determining the final energy.
Answer:
1) 51 m
2) Some energy was transformed to other forms. (This question)
3) 3.24 J
4) 45 J
5) 1020 J
Explanation:
100%
a man pulls a box with a force of 90.00 N directed along the handle which makes angle of 45 degrees with the ground. Find the horizontal and vertical components of this force.
Answer:
both are 45√2N
Explanation:
90 sin45°=90 cos45°=45√2N
Answer:
Explanation:
Both are 90sin(45°)= 63.6 N
A kayakeris paddling 2.50 m/s at an angle of 45° (northeast) and the current is moving 1.25 m/s at an angle of 315° (southeast). What is the kayaker's total velocity?
The kayaker has velocity vector
v = (2.50 m/s) (cos(45º) i + sin(45º) j )
v ≈ (1.77 m/s) (i + j )
and the current has velocity vector
w = (1.25 m/s) (cos(315º) i + sin(315º) j )
w ≈ (0.884 m/s) (i - j )
The kayaker's total velocity is the sum of these:
v + w ≈ (2.65 m/s) i + (0.884 m/s) j
That is, the kayaker has a velocity of about ||v + w|| ≈ 2.80 m/s in a direction θ such that
tan(θ) = (0.884 m/s) / (2.65 m/s) → θ ≈ 18.4º
or about 18.4º north of east.
a train moving at a speed of 15 m/s is accelerated to 45 m/s over a 12 s period. what is the acceleration?
Answer:
2.5 m/s²
Explanation:
Given:
v₀ = 15 m/s
v = 45 m/s
t = 12 s
Find: a
a = (v − v₀) / t
a = (45 m/s − 15 m/s) / 12 s
a = 2.5 m/s²
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The Question is based off this paragraph.
PARAGRAPH:
Two piles of heavy boxes must be lifted onto a shelf. Each pile has 20 boxes and each box is the same size and weight. Tom and Claudia are each responsible for a pile. Tom lifts each box straight up from the pile to the shelf. Claudia places a long, gradual ramp that leads from the pile to the shelf. She pushes each box up the ramp until it rests on the shelf.
QUESTION:
Tom pulls a muscle. He has to stop working to get an ice pack. Claudia continues to work and soon finishes her pile. Power is the rate of doing work. It’s calculated by dividing work by time (power = work ÷ time). Who had more power in this scenario? Why?
Answer: Claudia had more power. She did more work than Tom, and she did it in less time.
Explanation:that’s why the answer was !
Answer: Claudia had more power. She did more work than Tom when tom went to go get his ice pack.
HOPE THIS HELPS :D
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What other kinds of allotropes are there?
When a car speeds up when rounding a curve, what happens to its centripetal
acceleration?
A.) It decreases
B.) It increases
C.) It remains constant.
D.) It is zero.
How long is the racetrack if it takes a racecar 3.4 a traveling at 75 m/s to finish?
Answer:
255 metres
Explanation:
The answer to the question is actually quite simple. Since the car goes for 3.4 seconds, and it goes 75 metres every second, the answer is just 3.4 multiplied by 75 Metres.
What refers to the bending of light as it passes from one medium into another?
10. Which of the following arrangements of visible light colors shows decreasing wavelength?
A. red, orange, yellow, green, blue, indigo, violet
B. red, yellow, green, orange, violet, blue, indigo
C. violet, blue, green, orange, red, indigo, yellow
D. violet, indigo, blue, green, orange, yellow, red
12. What refers to the splitting of white light into seven different colors?
A. dispersion
B. refractive index
C. reflection
D. refraction
13. Refractive Index is a ratio between the speed of light in vacuum and .
A. speed of light in vacuum
B. speed of sound in vacuum
C. speed of light in a medium
D. speed of sound in a medium
15. Based on the colors of light, what color comes between red and yellow?
Answer:
9.Refraction
13.refractive index is the ratio of velocity of light in a vacuum to it's velocity I. a specified medium.
12.dispersion
14.Orange with a wavelength of about 585-620
I have no idea of number 10
One of the goals of psychology is to predict future behavior or mental processes. Which of the following scenarios best illustrates this goal?
A.
The psychologist measures Michael’s heart rate and bodily functions to better describe his behavior.
B.
The psychologist helps Michael develop strategies to manage his anxiety levels so he can focus on the game.
C.
The psychologist tells Michael that his basketball performance will improve when his anxiety levels are moderated.
D.
After careful research, the psychologist explains that Michael’s intense feelings of anxiety are hindering his basketball performance.
The statement 'the psychologist tells Michael that his basketball performance will improve when his anxiety levels are moderated' best illustrates an objective of psychology (Option C).
Psychology is a discipline that studies human behavior through the mind.The major objectives of psychology include describing, explaining, predicting, and modifying specific behaviors. Anxiety is one of the main focuses in physiology and there are many psychological treatments aimed at modifying this particular behavior.In conclusion, the statement 'the psychologist tells Michael that his basketball performance will improve when his anxiety levels are moderated' best illustrates an objective of psychology (Option C).
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Answer:
Explanation:
C
An object originally moving at a speed of 20. meters per second accelerates uniformly for 5.0 seconds to a
final speed of 50. meters per second. What is the acceleration of the object?
Answer:
92
Explanation:
Enter the number only - NO UNITS!
Calculate the speed of an object that travels 150 meters in 50 seconds.
Answer:
The answer is 3Explanation:
The speed of an object can be found by using the formula
[tex]s = \frac{d}{t} \\ [/tex]
d is the distance
t is the time taken
From the question we have
[tex]s = \frac{150}{50} = \frac{15}{5} \\ [/tex]
We have the final answer as
3 m/sHope this helps you
Answer:
110
Explanation:
i dont know
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Which scenario describes an effect of tornadoes on the environment? a section of forest that has been burned a path through a town with uprooted trees a town near the coast with heavy flooding a sandy beach that shows signs of erosion
Answer:
B; a path through a town with uprooted trees
Explanation:
took the quiz and got it right on edge2020!
The effect of tornadoes on the environment is a path through a town with uprooted trees. This, option B is correct.
What are tornadoes?It is the typical weather event that contains strong winds and leaves a path of destruction up to 50 miles long. It is also defined as the violently rotating column of air that touches the ground and is usually attached to a thunderstorm.
It is developed from a severe thunderstorm in warm, moist, and unstable air and extended up to 300 miles. The thunderstorms also generate heavy damage and devastate the environment in seconds and cause more fatalities.
A swirling, funnel-shaped, whirling wind is called a tornado and it is accompanied by hurricanes and storms. Strong tornadoes last for twenty minutes and the winds are between 200 mph to 300mph. The United States and Canada are mostly tornado-affecting countries.
The effect of tornadoes is a path through a town with uprooted trees and hence, the ideal solution is option B.
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This is Psychology. Define each of the following: Consensus, consistency, distinctiveness.
Answer:
Consensus: the extent to which other people behave in the same way in a similar situation.
Consistency: refers to the way in which minority influence is more likely to occur if the minority members share the same belief and retain it over time.
Distinctiveness: refers to the extent to which a specific action engaged in by an individual is unusual or uncommon for that particular individual
Diffraction occurs when waves _______ around the edge of a barrier?
Answer:
travels
Explanation:
hope this helps and have a blessed day
2
Select the correct answer.
What does the law of conservation of energy state?
OA.
Energy can be created from nothing.
OB.
Energy cannot be destroyed.
O C.
Energy cannot change forms.
OD.
The total amount of energy in a system changes continuously.
Answer:
D
Explanation:
The total amount of energy and matter in the Universe remains constant, merely changing from one form to another. The First Law of Thermodynamics (Conservation) states that energy is always conserved, it cannot be created or destroyed. In essence, energy can be converted from one form into another.
Answer: B) Energy cannot be destroyed
Explanation:
I had this question on a recent test and I got it right
Hope this helps! :)
Which of the following statements it's true about Sir isaac Newton
A.He discovered gravity when an apple fell on his head
B. He found that gravity was the strongest force
C. He made a connection between the mass of an object and the distance between them
D. He realized that the moon orbits Earth
Sir isaac Newton made a connection between the mass of an object and the distance between them.
According to Newton's law of universal gravitation, every object in the universe attracts each other with a force directly proportional to the product of the masses of the object and inversely proportional to the distance between the two objects.
[tex]F = \frac{Gm_1m_2}{R^2}[/tex]
where;
G is the gravitational constantm₁ and m₂ are the masses of the two objects R is the distance between the two objects
Thus, we can conclude that Sir isaac Newton made a connection between the mass of an object and the distance between them.
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If mass of the ball is 5kg how to calculate the potential energy?!
The mass of the ball is 5 kg and it is lifted 10 meters above the ground, its potential energy is 490 Joules.
What is Potential Energy?
Potential energy is the energy that an object possesses due to its position or condition. It is the energy that an object has stored within itself, ready to be converted into other forms of energy.
To calculate the potential energy of an object, we need to know its mass, the acceleration due to gravity, and its height above a reference point. The formula for potential energy is:
Potential Energy = Mass x Gravity x Height
where:
Mass is the mass of the object, in kilograms (kg)
Gravity is the acceleration due to gravity, which is approximately 9.8 m/s^2 on Earth
Height is the height of the object above a reference point, in meters (m)
If the mass of the ball is 5 kg, we can calculate its potential energy if we know its height above a reference point. For example, if the ball is lifted 10 meters above the ground, we can calculate its potential energy as:
Potential Energy = 5 kg x 9.8 m/s^2 x 10 m
Potential Energy = 490 Joules
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A 3 kg rubber block is resting on wet concrete. The coefficient of static friction is 0.3. What is the minimum force that must be applied to the block to make the block begin to accelerate?
Answer:
You would have to find the friction force of the rubber block which would be found with the equation of Normal force (mass*gravity) times cooeficient of friction which would give 8.82 N for the amount of friction and because you need more force than 8.82 N (assuming gravity is 9.8)
We need to find the frictional force of the rubber block. This is the normal force (mass × gravity) multiplied by the coefficient of friction, which gives us a friction quantity of 8.82N. This is because it requires a force greater than 8.82N (Gravity is 9.8)
What is coefficient of friction?Mathematically, = F/N, where F represents the frictional force and N represents the normal force. Because F and N are both measured in force units (such as Newtons or Pounds), the coefficient of friction is dimensionless.The friction coefficient is the ratio of the frictional force resisting movement of two contacting surfaces to the normal force pushing the two surfaces together.Both F and N are measured in units of force (such as Newtons or Pounds), so the coefficient of friction is dimensionless. The coefficient of friction has different values for static friction and sliding friction.In stiction, the frictional force resists the force applied to the object and the object remains stationary until the force of stiction is overcome. In kinetic friction, the frictional force opposes the motion of an object.To learn more about coefficient of friction, refer to:
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A 2000 kg truck and a 500 kg car are racing. The same amount of force is applied to each of them,
Answer:
Hh
Explanation:
Ghhhh
If two equal forces act on an object in opposite directions, what is the net
force? What is the objects acceleration?
Answer:
Net Force = 0
Explanation:
Causes objects to accelerate. Balanced Forces. Two equal forces push in opposite direction causing no change in motion causing net force = 0.
(03.07 MC)
A 660 kg car is travelling around a circular track of radius 55.0 m at 11.5 m/s.
Calculate the force and its direction that provides the centripetal force acting on the car to keep it
in the circular path. (3 points)
a) 24 N toward the center of the circle
b) 24 N along the line tangent to the circle
c) 1.587 E3 N along the line tangent to the circle
d) 1.587 E3 N toward the center of the circle
Answer: D) 1.587 E3 N toward the center of the circle
This is the same as saying 1.587*10^3 newtons, or we can say 1587 newtons
=================================================
Work Shown:
m = mass = 660 kilograms
v = velocity = 11.5 meters per second
r = radius of circle = 55.0 meters
-------------
F = centripetal force = inward pulling force toward center of circle
F = (m*v^2)/r
F = (660*11.5^2)/55
F = 1587
F = 1.587 * 10^3
F = 1.587 E 3
The "E 3" notation is what many calculators display scientific notation to be
The units for the force here are in newtons.
The force is pulling on the object toward the center of the circle, which helps keep the car on the circular path, rather than it going off on a tangent.
If a feather takes 2.5 seconds to drop 200cm, what is the speed of this feather
Answer:
80cm per second
Explanation:
What Machines that help you go faster
Answer:
If you mean for exercising then, The Treadmill. Purists may claim that treadmill running isn't "real" running. ...
The Elliptical Trainer. ...
The Stair-Climber. ...
The Cross-Country Skiing Simulator. are all machines that help you practice agility
Explanation:
Which describes radioactive decay of a substance?
A group of athletes are trying to turn a large wheel and axle to move a stone. What can they do to move the wheel with less effort?
A satellite with a mass of 5.60 E5 kg is orbiting the Earth in a circular path at 7.037E 6 meters from
the center of earth. It is moving at 7.50 E3 m/s. Determine the satellite's acceleration. (3 points)
a)7.99 m/s2
b)01.07 E-3 m/s2
c)O 1.14 E-6 m/s2
d)4.48 E6 m/s2
Answer:7.99 m/s^2
Explanation:
What happens when the two waves meet?
A.
They superimpose and remain at the same amplitude.
B.
They experience destructive interference and cancel each other out.
C.
They experience constructive interference and have twice the amplitude.
D.
They superimpose and have half of their original amplitude.
when two or more waves meet, they interact with other. The intersection of waves with other waves is called wave interference. wave interference may occur when two waves that are traveling I opposite directions meet. the two waves pass through each other, and this affects their amplitude
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During the Paleozoic Era glaciers moved through North American to carve out landforms.
Question 3 options:
True
False
