At t = 4.0 s, the elevator door opens and remains open for 5.0 s. The student immediately exerts a larger constant force on the box and the front of the box reaches the elevator door just as it start

to close.

() Calculate the magnitude of the new force that the student exerts.

Answers

Answer 1

Explanation:

Given,

mass of block = 30 kg

initial speed = 1.2 m/s

coefficient of friction = 0.20

time for elevator close and opening = 5.0 sec

for t= 0 sec to t= 4.0 sec

acceleration = 0

speed = 1.2 m/s

distance x= vt

at t=4 distance is x=4.8m

for t= 4.0 sec to next 5 second or t= 9.0 sec

the remaining distance for cover is

x= 16-4.8

x=11.2 m

using motion equation

x=vt+1/2at^2

11.2=1.2*5+1/2 0.5aa=0.416 m/s^2


Related Questions

Describe the particle motion of a longitudinal wave. Which type of medium (state of matter) would best carry them.
A: Solid
B: Liquid
C: Gas

Answers

Answer:

A solid

Explanation:

Hope this helped, Have a Great Day!!

Longitudinal waves can be produced in all the three states of matter.

What is meant by longitudinal wave ?

Longitudinal waves are the type of waves, in which the particles are travelling in the same direction of propagation of the waves.

Here,

The longitudinal waves are mechanical waves, which requires a medium for propagation.

The longitudinal waves have two components called compression and rarefaction.

The particles in the longitudinal waves can travel through all the phases such as solids, liquids and gases. These waves can be produced in all these states of matter.

Hence,

Longitudinal waves can be produced in all the three states of matter.

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Clara's grandfather is a captain of a cargo ship. He prefers to navigate his ship through the moderate neap tides. At these times, the line between Earth and the sun is at a right angle to the line between Earth and the moon. Which phase or phases of the moon describe this alignment?

Answers

Answer:

The phases are the first and third quarters.

Explanation:

During the first quarter of the moon phases, the line between Earth and the Sun is at a right angle to the line between Earth and the moon. At this time the moon has completed the first quarter of its orbit around the earth. At this point, half of the moon is fully reflecting light from the sun.

Also during the third quarter which is the last quarter, the line between the earth and the sun is at a right angle to the line between the earth and the moon. This is the time when the second half of the moon which was not illuminated during the first quarter becomes completely illuminated.

What does add stand for? hereee!!!!!!!!!!! Kelseeee

Answers

Add stands for example when you addition I math

Which of the following is not an example of acceleration?

A) A person jogging at 3 m/s along a winding path

B) A car stopping at stop sign

C) A cheetah running 27 m/s east

D) a plane taking off

Answers

The correct answer is C

What might happen if you were in a braking car and you weren’t wearing your seatbelt?

Answers

Answer:

well it depends on how fast for short its B

Explanation:

1. A car has a mass of 400 kg and is driving down a hill at 2 m/s/s. What is the force of the car?​

Answers

Answer:

l think the right answer is 4720

Explain what happens to the domain in a bar magnet if:

You cut the magnet in half
You drop the magnet onto a hard surface. How does each incident affect the magnetism of the magnet?

Answers

Answer:

1)Each one reinforces the magnetic fields of the others. Each one has a tiny north and south pole. If you cut one in half, the newly cut faces will become the new north or south poles of the smaller pieces.

2)Permanent magnets can lose their magnetism if they are dropped or banged on enough to bump their domains out of alignment. ... The reason that would be hard to bump a piece of iron and make it magnetic is because of the way vibrations propagate in the material.

Explanation:

what is thermonuclear fusion?​

Answers

Thermonuclear fusion is when matter is heated to a high degree
Thermonuclear fusion is a way of achieving nuclear fusion using extremely high temperatures. There are two types of thermonuclear fusion, controlled and uncontrolled.

URGENT ANSWER ASAP PLEASE

What is the relationship between memory and learning? Memory and learning are the same process. Memory is more important than learning. Memory is the foundation of all learning. Memory outlasts learning

Answers

Answer:

learning and memory are very closely related concept . Learning is the acquisition of silk or knowledge, while memory is the expression of what you've acquired.Another difference is the speed with which the two things happen if you acquire the new skill or knowledge slowly and laboriously, that's learning

Answer: I took a test that had this question and the answer was Memory is the foundation of all learning. I hope this helps

i dont know what subject this is sorry but it would help if someone could answer this

Answers

Answer: C

Explanation: We report cell-to-cell movement of mitochondria through a graft junction. Mitochondrial movement was discovered in an experiment designed to select for chloroplast transfer from Nicotiana sylvestris into Nicotiana tabacum cells. The alloplasmic N. tabacum line we used carries Nicotiana undulata cytoplasmic genomes, and its flowers are male sterile due to the foreign mitochondrial genome. Thus, rare mitochondrial DNA transfer from N. sylvestris to N. tabacum could be recognized by restoration of fertile flower anatomy. Analyses of the mitochondrial genomes revealed extensive recombination, tentatively linking male sterility to orf293, a mitochondrial gene causing homeotic conversion of anthers into petals. Demonstrating cell-to-cell movement of mitochondria reconstructs the evolutionary process of horizontal mitochondrial DNA transfer and enables modification of the mitochondrial genome by DNA transmitted from a sexually incompatible species. Conversion of anthers into petals is a visual marker that can be useful for mitochondrial transformation.

How Negative Points Works

btw help me with this

How much does the sky weigh?

Answers

Answer:

it weighs 237469812734t7162341873498273417234321476281736481273648123764812736481723648273648137468127364872364 million pounds :)

Explanation:

Answer:

This is a dumb question.

Explanation:

The 'sky' does not weigh anything.

A Red-Tailed Hawk leaves its nest and flies 100.0 meters across the sky in 20 seconds, when it spots a garter snake on the ground below. It then flies 50.0 meters in 5.0 seconds to catch the snake. What was the hawk's average speed over his entire journey?

Answers

Answer:

7.5 m/s

Explanation:

A red tailed hawk leaves its nest and flies 100 meters across the sky in 20 secs

Speed 1= distance/time

= 100/20

= 5m/s

When it spots a garter snake on the ground it flies 50 meters in 5 secs

Average speed= distance /time

= 50/5

= 10 m/s

Therefore the average speed of the hawk over the entire journey can be calculated as follows

= 10+5/2

= 15/2

= 7.5 m/s

why resistors made from later of carbon?​

Answers

Explanation:

The carbon film acts as the resistive material to the electric current. Hence, the carbon film blocks some amount of electric current.

Therefore, these resistors can withstand at higher temperatures without any damage.

hope it helps !

Answer:

because

Explanation:

carbon composition are suitable to withstand high energy pulses while having a relatively for small size for this reason resistors made from later carbon

Why does a heavy chair not move by itself? ?

Answers

Because of inertia, an object at rest rends to stay at rest. An object in motion tends to keep moving at a constant speed in a straight line

what is the main reason why people use machines

Answers

Answer:

Machines are faster and more efficent

Explanation:

Answer: Machines makes work easier and save some time and is very fast. For example, an elder can't walk or stand very long, so people made a motorized wheelchair!

Explanation:

F = m x a. A ball of mass 0.35kg rolls on a smooth surface hits another object at rest and of mass 7kg. The second object gets an acceleration of 1.5m/s2. What acceleration does the ball get? Use newton’s third law.
Please show the working and thankyouu!!

Answers

Answer:

The acceleration the ball gets = 30 m/s²

Explanation:

The given parameters are;

The mass of the first ball that hits an object, m₁ = 0.35 kg

The mass of the object hit by the ball, m₂ = 7 kg

The acceleration given to the second object, a₂ = 1.5 m/s²

Let the a₁ represent the acceleration the ball gets

Newton's third law states that action and reaction are equal and opposite, therefore, the force exerted on a body A by a body B is equal to the force exerted on the body B by the body A;

Therefore, we have;

The force exerted on the object, F₂ = m₂ × a₂ = 7 × 1.5 = 10.5 N

The force the ball exerts on the object = F₁ = m₁ × a₁ = 0.35 × a₁

By Newton's third law, F₁ = F₂, which gives;

m₁ × a₁ = m₂ × a₂

0.35 × a₁ = 10.5

a₁ = 10.5/0.35 = 30

The acceleration the ball gets = a₁ = 30 m/s².

a disk initially at rest rotates with constant angular acceleration through an angel of 50 rad in 5 sec find the angular speed of the disk just after 3 sec. please step by step

Answers

Recall the formula,

θ = ωt + 1/2 α t ²

where ∆θ = angular displacement, ω₀ = initial angular speed (which is zero because the disk starts at rest), α = angular acceleration, and t = time. Solve for the acceleration with the given information:

50 rad = 1/2 α (5 s)²

α = (100 rad) / (25 s²)

α = 4 rad/s²

Now find the angular speed ω after 3 s using the formula,

ω = ω₀ + α t

ω = (4 rad/s²) (3 s)

ω = 12 rad/s

Yvonne and Eddy are riding a ferris wheel at the Dade County Fair. If the radius of the ferris wheel is 15.0 m, and it rotates once every 35.0 seconds, what is the linear speed of Yvonne and Eddy?
A- 2.69 m/s
B- 1.79 m/s
C- 4.52 m/s
D- 0.82 m/s

Answers

Answer:

2.69 m/s

Explanation:

The equation used is v=(2πr)/T

( (2) (π) (15.0) ) / (35) = 2.69

(i) Candidates and parties with a lot of money may not be sure of their victory but they do enjoy a big and unfair advantage over smaller parties and independents. (ii) In some parts of the country, candidates with criminal connection have been able to push others out of the electoral race and to secure a ticket from major parties. (iii) Some families tend to dominate political parties. Tickets are distributed to relatives from these families.

Answers

Answer:

Challenges to a fair election       

Explanation:

All the point mention or given in the question are challenges to a fair and free election process.

Election may be defined as an procedure to select or elect any person as a member of an organization or as an official. Here people cast their vote to their favorite person whom they want to choose and elect as their official. Though election is a just and fair process but there are several challenges to it.

It is seen that parties with more money try to influence their voters. Some candidates may have contact with the criminals and they use these contacts to play unfair means and try to win the election. While there are some families which have a dominance in the political parties and they try to win their family members in the election.  

A car accelerates from rest at a rate of 4 m/s’2 . How many seconds will it take the car to reach a final speed of 16m/s

Answers

Answer:

t = 4 [s]

Explanation:

To solve this problem we must use the following equation of kinematics.

[tex]v_{f}=v_{o}+a*t[/tex]

where:

Vf = final velocity = 16 [m/s]

Vo = initial velocity = 0

a = acceleration = 4 [m/s²]

t = time [s]

Now replacing:

[tex]16=0+4*t\\t = 16/4\\t = 4[s][/tex]

1. A record with a radius of 0.3m spins in a clockwise circle with a centripetal
acceleration of 4.7 m/s2. How long does it take the record to make one revolution?
(Hint: Find tangential velocity first!)

Answers

Solve for the linear/tangential speed:

a = v²/r

where a = centripetal acceleration, v = speed, and r = radius.

4.7 m/s² = v²/(0.3 m)

v² = (0.3 m) (4.7 m/s²)

v ≈ 3.96 m/s

For every time the record completes one revolution, a fixed point on the edge of the record travels a distance equal to its circumference, which is 2π (0.3 m) ≈ 1.88 m. So if 1 rev ≈ 1.88 m, then the angular speed of the record is

(3.96 m/s) (1/1.88 rev/m) ≈ 7.46 rev/s

Take the reciprocal of this to get the period:

1 / (7.46 rev/s) ≈ 0.134 s/rev

So it takes the record about 0.134 seconds to complete one revolution.

10. On Christmas Eve night when all the Who's are sleeping, are they still using energy? Explain this by using
the Law of Conservation of Energy.

Answers

Answer:

Using  the Law of Conservation of Energy is described below in details.

Explanation:

The law of conservation of energy tells that energy can not be produced nor stopped - only transformed from one kind of energy to different. This indicates that a system constantly has the same quantity of energy, unless it's combined from the outside. This law is extremely significant because it is a really easy process to figure out relevant knowledge about an article.

A particle is launched at an angle of 37° from horizontal. If the horizontal velocity component is 7.65 meters/second, what is the resultant velocity of the particle?

Answers

Answer:

R = 9.58 m/s

Explanation:

cos(37) = (7.65 m/s)/R

R = (7.65 m/s)/cos(37)

R = 9.58 m/s

How many molecules of water are found in this formula--6H2O?

Answers

Answer:

6 the number infront of H2O is the amount of molecules it is

Explanation:

How long would a circuit be connected to produce a current of 0.65 A with a charge of 380 C?

Answers

Answer:

what grade are you dude

If a rock is thrown into a still pond creating ripples in the water, does this situation represent a transfer of kinetic energy?

Answers

I think it’s kinetic energy but I’m not sure hope this helps!

PLEASE HELP URGENT 1. You put 1 gram of salt into 1 liter of water and stir. The resulting liquid is an example of
A. A pure substance.
B. a homogeneous mixture.
C. a heterogeneous mixture.
D. an immiscible mixture.

Answers

C, is correct.

Have a nice day!

Which of the following is NOT an example of convection?

Answers

Answer:

HEAT?

Explanation:

A person gets a suntan on a beach is not an example of convection. Therefore, the correct option is option C.

What is convection?

The process of convection involves the movement of such a heated fluid, including such air or water, in order to transfer heat. Natural convection is caused by the fact that most fluids have a propensity to expand when heated, becoming less dense and rising due to the increased buoyancy.

Natural convection is caused by the fact that most fluids have a tendency to expand when heated, becoming less dense and rising due to the increased buoyancy. The air inside a heated room or the water inside a kettle are heated uniformly thanks to circulation brought on by this effect. A person gets a suntan on a beach is not an example of convection.

Therefore, the correct option is option C.

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Your question is incomplete but most probably your full question was,  

Which one of the following is not an example of convection?

a) Smoke rises above a fire.

b) An eagle soars on an updraft of wind.

c) A person gets a suntan on a beach.

d) Spaghetti is cooked in water.

e) An electric heater warms a room.  

which way is the force of inertia pulling?

Answers

The force of inertia pushes forward . Inertia is an object tendency to continue foward . But pushes opposite the force as the other force

pleass help answer the question in the picture

Answers

Answer:

I think C

Explanation:

It’s A, it’s not C that’s is wrong. The correct answer is A
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