An object of mass m is hanging by a string from the ceiling of an elevator. The elevator is moving down at constant speed. What is the tension of the string?

A. Zero
B. Equal to mg
C. Less than mg
D. Greater than mg​

Answers

Answer 1

Answer:

D. Greater than mg​

Explanation:

According to Newton’s second law of motion, the net force equals mass times acceleration. We are going to use a free body diagram (force diagram) to show that the equation of the motion is given by

T – mg = – ma

Thereby,

T = mg – ma

and the answer is: (d)

D. Greater than mg​

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Related Questions

Water has higher specific heat than aluminum. This is all what you should know to answer following questions. An aluminum rod of mass 1 kg at temperature of 80^0C is placed into 1l of water of temperature 10^0C . there is no heat exchange with surroundings. Which material experiences greater change in temperature while system is reaching the thermal equilibrium

Answers

Answer:

The Aluminum

Explanation:

With a larger specific heat, water requires more heat to raise its temperature by a temperature degree.

In this system, with equal masses of water and aluminum, the heat moving from the aluminum lowering its temperature by one degree is not sufficient to raise the water temperature by one degree.

How is heat transferred by convection?

Answers

Answer:

Convective heat transfer is the transfer of heat between two bodies by currents of moving gas or fluid. In free convection, air or water moves away from the heated body as the warm air or water rises and is replaced by a cooler parcel of air or water.

Explanation:

Hope this helped and have a great day

Heat can be transferred by convection through liquids. Heat travels where warmer liquid rises and cooler liquid sinks. An example of this can be heating up a pot of water. Hope this helps!

A ball is dropped from an 80.0 m building. What is the ball's velocity after 3.00 s? Use an order-of-magnitude estimation to identify the correct choice.
A. -2.9 m/s
B. -29.4 m/s
C -8.8 m/s
D. -88.3 m/s​

Answers

Answer:b

Explanation:

-29.4 m/s

The velocity of the ball dropped from 80 m if it reaches the ground within 3 seconds is 26.6 m/s. If it is in midway within this time, then the velocity will be 29.4 m/s.

What is velocity ?

Velocity of a moving object is the measure of its distance travelled per unit time. Velocity is a vector quantity having both magnitude and direction. Acceleration is the rate of change in velocity.

Given that, height of the building = 80 m

the ball is moving downwards by acceleration due to gravity g = 9.8 m/s².

Then after 3 seconds, the velocity of the ball is calculated as follows:

velocity = acceleration × time

v = 9.8 m/s²  × 3 s = -29.4 m/s

If the ball reaches the ground within the time of 3 s, then, the velocity is:

v = 80 m/3s = 26.6 m/s.

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The 6 strings on a guitar all have about the same length and are stretched with about the same tension. The highest string vibrates with a frequency that is 4 times that of the lowest string. 1)If the strings are made of the same material, how would you expect the diameters of the lowest and highest strings to compare

Answers

Answer:

not sure i need points

Explanation:

a load of 600 N is lifted using a first class lever applying an effort of 350 N. If the distance between the fulcrum and the effort is 60 cm and the distance between the load and the fulcrum is 30cm, calculate it's efficiency​

Answers

Explanation:

(a) A machine is a device by which we can either overcome a large resistive force at some point by applying a small force at a convenient point and in a desired direction or by which we can obtain a gain in the speed.

(b) An ideal machine is a machine whose parts are weightless and frictionless so that which there is no dissipation of energy in any manner. Its efficiency is 100%, i.e. the work output is equal to work input.

electron and proton are projected with same velocity normal to the magnetic field which one will suffer greater deflection​? why

Answers

Answer:

Explanation:

The deflection of a charged particle by a magnetic field is proportional to its electric charge and to its velocity.   The deflection is also inversely proportional to its mass.   So given a proton and an electron going at the same velocity in a magnetic field and having equal (but opposite) electric charge the electron will deflect much more since the ratio of the masses is 1836.

Five ramps lead from the ground to the second floor of a workshop, as sketched below. All five ramps have the same height; ramps B, C, D and E have the same length; ramp A is longer than the other four. You need to push a heavy cart up to the second floor and you may choose any one of the five ramps.Assuming no frictional forces on the cart, which ramp would require you to do the least work?

Answers

The mechanical advantage of ramp A is greater than others and it will require the least force to move the load to greater distance.

Let the height of the ramp = hLet the length of ramp B, C, D and E = LLet the length of the ramp A = 2L

The mechanical advantage of the ramp is calculated as follows;

[tex]M.A = \frac{L}{h}[/tex]

The mechanical advantage of the ramp B, C, D and E is calculated as;

[tex]M.A = \frac{L}{h} \\\\[/tex]

The mechanical advantage of the ramp A is calculated as follows;

[tex]M.A = \frac{2L}{h} \\\\M.A = 2(\frac{L}{h} )[/tex]

Since the length of the ramp A is greater than other ramps, the mechanical advantage will be greater and it will require the least force to move the load to greater distance.

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Elevations on the tongue are called
sulci
taste buds
papillae
gyri

Answers

Answer:

Papillae is correct

Explanation:

hope it helps you

Answer:

Papillae is the correct answer of this question

Two blocks are set in a pully system as shown in fig below. Block A sits on the frictionless table while block B hags freely. The pully is light and frictionless towards the light string that runs over it. If the Block A has mass of 3.4 kg and Block has 3.5 kg, what would be the magnitude of the acceleration (in ms-2) of the blocks? [g = 9.8 ms=2]​

Answers

Answer:

Explanation:

F = ma

a = F/m

a = mBg / (mB + mA)

a = 3.5(9.8)/(3.5 + 3.4)

a = 4.971014...

a = 5.0 m/s²

If you want to use individual Free Body Diagrams

mass A will have downward weight and upward normal forces equal at mAg

and a horizontal force of string tension T

F = ma

T = mAa

mass B will have a downward force of mBg and an upward force of T

mBg - T = mBa

substitute for T

mBg - mAa = mBa

mBg = a(mB + mA)

a = mBg / (mB + mA)   which is identical to the above answer.

what are saturated and non saturated vapour? ​

Answers

Answer:

A saturated vapour is one that is in balance with its own liquid. Space is considered to be unsaturated if it contains fewer vapours than the maximum amount it can retain at a given temperature. Saturated vapour pressure is unaffected by volume, although it rises as temperature rises.

Explanation:

Rachel drops a ball from a hot–air balloon while her friend Lisa is watching her from the ground. Which statement about the ball's motion is true from Lisa's point of view?

Assume that there is no air resistance and the hot–air balloon is moving horizontally.


A. The ball drops to the ground along a straight–line path.


B.When the ball lands, the hot–air balloon will be ahead of it.


C. When the ball lands, the hot–air balloon will be behind it.


D. When the ball lands, the hot–air balloon will be directly above it.

Answers

Answer:

According Lisa, both the ball and the balloon have the same forward velocity of Vx.

(D) is correct

A man walks 30m to the west, then 5m to the East in 45 seconds. What is the total distance walked?

Answers

Answer:

In this problem basically we will use directions to find displacement and distance .

(Keep in mind that displacement is vector while distance is scalar quantity)  

And then we will use displacement and distance to find average velocity and average speed.

Explanation:

Conservation of Energy Roller Coaster A roller coaster cart of mass 100kg travels on a track with one loop. Fill in blanks A-H. А. KE=OJ PE=120000J h= А. V= B B KE=___CE PE=60000J h= _D V= E KE=__F PE=40000J h=__G_ V= KE= PE= h=Om v= K D E F G H K​

Answers

(a) The height of the roller coaster at 120,000 potential energy is 122.45 m.

(b) The velocity of the roller coaster at 0 J kinetic energy is 0.

(c) The height of the roller coaster at 60,000 potential energy is 61.23 m.

(d) The velocity of the roller coaster at 60,000 J kinetic energy is 34.64 m/s.

(e) The height of the roller coaster at 40,000 potential energy is 40.82 m.

(f) The velocity of the roller coaster at 80,000 J kinetic energy is 40 m/s.

The given parameters:

mass of the roller coaster, m = 100 kg

When the kinetic energy = 0 and potential energy = 120,000 J

The height of the roller coaster is calculated as follows;

P.E = mgh

[tex]h = \frac{P.E}{mg}\\\\h = \frac{120,000}{100 \times 9.8} \\\\h = 122.45 \ m[/tex]

Since the kinetic energy = 0, the velocity of the roller coaster = 0

When the potential energy, P.E = 60,000 J, the kinetic energy, K.E is calculated as;

P.E + K.E = M.A

P.E + K.E = 120,000

60,000 + K.E = 120,000

K.E = 120,000 - 60,000

K.E = 60,000 J

The height of the roller coaster at 60,000 potential energy is calculated as follows;

[tex]h = \frac{P.E}{mg} \\\\h = \frac{60,000}{100 \times 9.8} \\\\h =61.23 \ m[/tex]

The velocity of the roller coaster at 60,000 J kinetic energy is calculated as follows;

[tex]K.E = \frac{1}{2} mv^2\\\\v^2 = \frac{2K.E}{m} \\\\v = \sqrt{ \frac{2K.E}{m}} \\\\v = \sqrt{ \frac{2\times 60,000}{100}}\\\\v = 34.64 \ m/s[/tex]

When the potential energy, P.E = 40,000 J, the kinetic energy, K.E is calculated as;

P.E + K.E = M.A

40,000 + K.E = 120,000

K.E = 120,000 - 40,000

K.E = 80,000

The height of the roller coaster at 40,000 potential energy is calculated as follows;

[tex]h = \frac{P.E}{mg} \\\\h = \frac{40,000}{100 \times 9.8} \\\\h = 40.82 \ m[/tex]

The velocity of the roller coaster at 80,000 J kinetic energy is calculated as follows;

[tex]v = \sqrt{\frac{2K.E}{m} } \\\\v = \sqrt{\frac{2\times 80,000}{100} } \\\\v = 40 \ m/s[/tex]

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Find the self-inductance of a 1700-turn solenoid 55 cm long and 4.0 cm in diameter. Express your answer with the appropriate units.

Answers

The self-inductance of the solenoid is 8.25 mH.

The given parameters;

number of turns, N = 1700 turnlength of the solenoid, l = 55 cm = 0.55 mdiameter of solenoid, d = 4 cmradius of the solenoid, r = 2 cm = 0.02 m

The area of the solenoid is calculated as follows;

[tex]A = \pi r^2\\\\A = \pi \times (0.02)^2\\\\A = 0.00125 \ m^2[/tex]

The self-inductance of the solenoid is calculated as follows;

[tex]L = \frac{\mu_o N^2 A }{l} \\\\L = \frac{(4\pi \times 10^{-7}) \times 1700^2 \times 0.00125}{0.55} \\\\L = 0.00825 \ H\\\\L = 8.25\ mH[/tex]

Thus, the self-inductance of the solenoid is 8.25 mH.

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Which of the following is a fundamental unit of the SI system of units?
A) kilometer
B) joule
C) kilogram
D) gram
E) newton

Answers

The answer is C) kilogram

The SI unit in the given options is kilogram, the correct option is C.

What is SI unit?

The most common unit of measurement is the standard unit. These units are standardized, which means that everyone understands an object's size, weight, and other properties.

Standard Units of Measurement have fixed values that cannot be changed.

The International System of Units, abbreviated SI in all languages and sometimes pleonastically as the SI system, is the modern version of the metric system and the world's most widely used measurement system.

The SI is a coherent system of units of measurement that begins with seven base units: the second (symbol s, the unit of time), the metre (m, length), the kilogram (kg, mass), the ampere (A, electric current), and so on.

Thus, the correct option is C.

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What are the 7 different states of matter in Chemistry?How many states of matter are there?

Answers

Answer:

The 7 states of matter are solid, loquid, gas, fermionoc condensate, quark gluton plasm, bose einetein condensate amd ionised plasm but its usually only 3 they teach you

Answer:

7

Explanation:

solid, liquid,gas,fermionoc condensate,quark glutton plasm,bose einetein condensate amd ionised plasm.

It velocity of light scalar or vector equality ​

Answers

Answer:

velocity is a vector quantity

Explanation:

velocity is a vector quantity because it has a mass and a direction

Please help me with this problem​

Answers

Answer:

Summertime

Explanation:

the sun never sets south of the Antarctic circle in the summertime.

Uranus (mass = 8.68 x 1025 kg) and its moon Miranda (mass = 6.59 x 1019 kg) exert a gravitational force of 2.28 x 1019 N on each other. How far apart are they? cs [?] x 10?'m Coefficient (green) Exponent (yellow) Enter​

Answers

Answer:

Explanation:

F = GMm/d²

d = √(GMm/F)

d = √(6.674e-11(8.68e25)(6.59e19) / 2.28e19)

d = 1.29398e8 = 1.29 x 10^8 m  center to center

Answer:

1.29 x 10^8 m  apart

Explanation:

Works in Acellus!

Please Help


A projectile fired over level ground has an initial total velocity of 41.3 m/s. It is in the air for 5.1 s. What is the x-component of the projectile's initial velocity?

Answers

Answer:

Explanation:

In the vertical analysis assuming launch from ground level.

0 = 0 + (41.3sinθ)(5.1) + ½(-9.8)5.1²

(41.3sinθ)(5.1) = ½(9.8)5.1²

(41.3sinθ) = ½(9.8)5.1

sinθ = ½(9.8)5.1/41.3

sinθ = 0.60508...

θ = 37.235°

vx = 41.3cos37.235

vx = 32.881452...

vx = 32.9 m/s

Lab report on velocity of sound

Answers

This is your answer I hope you have everything that you need

What is the voltage if the current is 4 A and the resistance is 10 Ω?

Answers

Answer:

40 volts

Explanation:

Use the equation [tex]V=IR[/tex]

[tex]V=(4)(10)[/tex]

[tex]V=40[/tex]

HELP PLS!!

A 3 kg mass is raised a distance of 14 m above the earth by a vertical force of 93 N.
a
The gain in potential energy of the mass, to 3 significant figures, is:

Answers

Hi there!

We know that:

U (Gravitational Potential Energy) = mgh

Where:

g = acceleration due to gravity (m/s²)

m = mass (kg)

h = height/displacement (m)

Plug in the values:

U = 3 × 9.8 × 14 = 412 J

A Pump discharges water at 1MPaa and 165 deg C. Determine the specific volume and internal energy of the water at the discharge point.

Answers

This problem is describing a pump from which water is discharged at 1 MPa and 165 °C and is asking for the specific volume and internal energy at those conditions, thus, we can use the steam tables for resolving this requirement.

First of all, we need to remember that water can be a saturated liquid, vapour or liquid-vapour mixture, and this is determined for the temperature and pressure it is at.

In this case, we find that at 165 °C the saturation pressure is about 0.6178 MPa; this means we are referring to a saturated liquid so that both the specific volume and internal energy can be simply read from the steam tables as vf and uf as follows:

[tex]v=0.001127\frac{m^3}{kg}\\\\u=761.67 \frac{kJ}{kg}[/tex]

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A farm tractor starting from the rest attains a speed of 36000 m/s after covering a distance of 2000 m. Work out the magnitude of the net force the tractor weighs 5000 kg.​

Answers

Answer:

the answer is 3,888.7

Explanation:

Hope this answer helped!:)

A car is driving 12m/sec, has to stop suddenly because a pedestrian dashes out in front of the car. If the coefficient of kinetic friction between the tires and parking lot is ∪=60

what is the time, after the breaks are applied, before the car comes to a stop? Sketch the velocity time graph for the car's motion from the instant the breaks are applied until the car comes to a stop.

Answers

Answer:

Approximately [tex]2\; \rm s[/tex], assuming that the floor of this parking lot is level, [tex]\mu_{\rm k} = 0.60[/tex], and [tex]g = 9.81\; \rm m\cdot s^{-2}[/tex].

Explanation:

Let [tex]m[/tex] denote the mass of this vehicle. Weight of this vehicle: [tex]m\, g[/tex].

If the floor of this parking lot is level, the normal force on this vehicle would be equal to its weight: [tex]N = m \, g[/tex].

Given that [tex]\mu_{\rm k}[/tex], the kinetic friction between this vehicle and the ground would be consistently [tex]\mu_{\rm k} \, N = \mu_{\rm k} \, m \, g[/tex] until the vehicle comes to a stop.

Assuming that all forces on this vehicle other than friction are balanced. The net force of this vehicle during braking would be [tex](-\mu_{\rm k} \, m \, g)[/tex] (negative because this force is opposite to the direction of the motion.)

By Newton's second law of motion, the acceleration of this vehicle would be:

[tex]\begin{aligned}a &= \frac{F_\text{net}}{m} \\ &= \frac{-\mu_{\rm k} \, m \, g}{m} \\ &= -\mu_{\rm k}\, g \\ &= -0.60 \times 9.81\; \rm m\cdot s^{-2} \\ &= -5.886\; \rm m\cdot s^{-2}\end{aligned}[/tex].

In other words, braking would reduce the velocity of this vehicle by a constant [tex]5.886\; \rm m\cdot s^{-1}[/tex] every second until the vehicle comes to a stop. Calculate the time it would take to reduce the velocity of this vehicle from [tex]v_{0} = 12\; \rm m\cdot s^{-1}[/tex] to [tex]v_{1} = 0\; \rm m\cdot s^{-1}[/tex]:

[tex]\begin{aligned}t &= \frac{v_{1} - v_{0}}{a} \\ &= \frac{0\; \rm m\cdot s^{-1} - 12\; \rm m\cdot s^{-1}}{-5.886\; \rm m \cdot s^{-2}} \\ &\approx 2.0\; \rm s \end{aligned}[/tex].

Acceleration is the slope of the velocity-time graph. Since the acceleration here is constant, the velocity-time graph of this vehicle would be a line with a negative slope.

Match the sport/physical activity in column B with the primary physical fitness component needed to perform it in column A . Write the letters of your answer in your activity notebook.

1. Power

A. Patintero

2. Speed

B. Marathon

3. Balance

C. dodgeball / tamaan bata

4. Coordination

D. 100m sprint

5. Flexibility

E. badminton and table tennis

6. Muscular Strength

F. exercise and proper diet


7. Agility

G. hopscotch/piko

8. Cardiorespiratory Endurance

H. Shotput

9. Reaction time

I. Archery


J. Leg Splits and yoga poseso



sagutan po plss

Answers

. Power

Patintero

, also known as harangang-taga or tubigan, (Intl. Translate: Escape from the hell or Block the runner) is a traditional Filipino children's game. Along with tumbang preso, it is one of the most popular outdoor games played by children in the Philippines.[1]

2. Speed

The Barkley Marathons

is an ultramarathon trail race held in Frozen Head State Park near Wartburg, Tennessee. If runners complete 60 miles (97 km) this is known as a "fun run." The full course is about 100 miles (160 km). The race is limited to a 60-hour period and takes place in late March or early April of each year.

Explain why a tiny 1.5 V cell can operate a calculator for a year, while a much larger 1.5 V cell burns out in a few hours in a tiny robot. I WILL CHOOSE BRAINIEST!! PLEASE HELP

Answers

The reason why a tiny 1.5 V cell can operate a calculator for a year, but would burn out in a few hours in a tiny robot is because the power demands of the calculator are way less than that of the tiny robot.

What controls how long a cell lasts ?

Cell capacity is measured by the amount of Amps and Amp Hour (A.H.) capacity for how long a battery can endure.

On the label or in the user's manual, batteries mention their reserve capability, which specifies the approximate amount of time they can operate between charges. You might notice a shorter or longer battery life if your circuit uses more or less power than this hypothetical circuit. Calculate the battery's entire capacity and divide it by the power of your circuit to see how long it can survive.

Load current, which is influenced by the power of the linked item, influences how quickly the battery's electrical capacity will be used up.

The reason the 1.5 V cell would operate the calculator for a year and yet die in a few hours with the robot is that the robot has a much higher load current than the calculator.

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Use a trigonometric equation to
determine the leg of this triangle.
10 m
[?]
m
30°

Answers

Answer:

5m

Explanation:

x=?

[tex]sin30^{0} =\frac{x}{10}[/tex]

[tex]x=10sin30^{0} =10(0.5)=5[/tex]

Hope this helps

How do I resolve moments about the point P?

Answers

Answer:

By applying the definition of torques ( [tex]\vec \tau = \vec r \times \vec F[/tex] ) and them remembering a few tricks.

Namely: if you wrap your RIGHT hand fingers around something and stick your thumb out, the direction your finger wraps gives you the verse of rotation and the thumb the orientation of the torque. Bottom force (4N) will give a counterclockwise rotation, torque is pointing up; top force (3N) will give a clockwise rotation and its torque its pointing down (read up and down as if the sheet the image is printed on is on your table).

In terms of magnitude the trick is easy: You want to multiply the intensity of the force (3N and 4N) by the distance between the point and the line the force it is applied to (that is, you don't care about the length of r itself, but the distance at a right angle, which is 0.9 and 0.8m respectively.

At this point, assuming "upwards" (relative to the plane of the sheet that is) torques positive, the 3N force gives you a torque of [tex]- 3N \times 0.9m = - 2.7N\cdot m[/tex] and the 4N force provides [tex]+4N\times 0.8 m = +3.2 N\cdot m[/tex]

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What arguments does Hamilton make in support of lifetime tenure? what reason would support a counterclaim what happened to indentured servants who were freed 4. Fix the following sentence. First, tell me what is missing, then make thenecessary changes:The children on the bus.5. What is tense? x + y = 8 Now let x = 7. What is y? .1/2 of David's money is2/3 of Henry's money.(a) Express David's money as a fraction of Henry's money Diseases brought by explorersdid not affect the population of the Caribbean.killed only 200 Tainos in Hispaniola.wiped out entire cultures.slightly affected the population of Central America Which are elements of art?A. line and textureB. emphasis and shapeC. contrast and unityD. rigor and flexibility Explain why the order in an ordered pair is important Tim's phone service charges $24.25 plus an additional $0.18 for each text message sent per month. If Tim's phone bill was $28.75, which equation could be used to find how many text messages, x, Tim sent last month? what is the difference between registered and certified mail En tu opinin, cmo sera la familia ideal? Translate to an equation and solve. Let x be the unknown number.30% of 26 is what number? An information of a 500GB is transferred at the speed of 10MB/s. Calculate the full time the information will be transfer. What role does physical health play into nutrition? Innovative technology can enhance parenting byacting as a babysitterdeveloping social skillsmonitoring heart ratereducing the cost of raising a child Can anyone help me please anyone please What is the slope of the equation .Explain why the two figures below are not similar. Use complete sentences andprovide evidence to support your explanation. (10 points) if the amplitude of a sound wave is tripled, the intensity will: