A man weighs himself twice in an elevator. When the elevator is at rest, he weighs 824 N; when the elevator starts moving upward, he weighs 932 N. Most nearly how fast is the elevator accelerating, assuming constant acceleration?

a. 0.64 m/s
b. 1.1 m/s^2
c. 1.3 m/s
d. 9.8 m/s^2

Answers

Answer 1

Answer: c. 1.3 m/s^2

Explanation:

When he is at rest, is weight can be calculated as:

W = g*m

where:

m = mass of the man

g = gravitational acceleration = 9.8m/s^2

We know that at rest his weight is W = 824N, then we have:

824N = m*9.8m/s^2

824N/(9.8m/s^2) = m = 84.1 kg

Now, when the elevators moves up with an acceleration a, the acceleration that the man inside fells down is g + a.

Then the new weight is calculated as:

W = m*(g + a)

and we know that in this case:

W = 932N

g = 9.8m/s^2

m = 84.1 kg

Then we can find the value of a if we solve:

932N = 84.1kg*(9.8m/s^2 + a)

932N/84.1kg = 11.1 m/s^2 = 9.8m/s^2 + a

11.1 m/s^2 - 9.8m/s^2 = a = 1.3 m/s^2

The correct option is C


Related Questions

a ball of diameter 10 cm and mass 10 grams is dropped in a container of water. the cross sectional area of the container is 100 cm2.. what is the change in the height of the water column

Answers

Answer:

h = 9.83 cm

Explanation:

Let's analyze this interesting exercise a bit, let's start by comparing the density of the ball with that of water

       

let's reduce the magnitudes to the SI system

         r = 10 cm = 0.10 m

         m = 10 g = 0.010 kg

         A = 100 cm² = 0.01 m²

the definition of density is

          ρ = m / V

the volume of a sphere

         V = [tex]\frac{4}{3} \ \pi r^{3}[/tex]

          V = [tex]\frac{4}{3}[/tex] π 0.1³

          V = 4.189 10⁻³ m³

let's calculate the density of the ball

           ρ = [tex]\frac{0.010}{4.189 \ 10^{-3} }[/tex]

           ρ = 2.387 kg / m³

the tabulated density of water is

         ρ_water = 997 kg / m³

we can see that the density of the body is less than the density of water. Consequently the body floats in the water, therefore the water level that rises corresponds to the submerged part of the body. Let's write the equilibrium equation

            B - W = 0

            B = W

             

where B is the thrust that is given by Archimedes' principle

           ρ_liquid  g V_submerged = m g

           V_submerged = m / ρ_liquid

we calculate

            V _submerged = 0.10 9.8 / 997

             V_submerged = 9.83 10⁻⁴ m³

The volume increassed of the water container

           V = A h

            h = V / A

let's calculate

            h = 9.83 10⁻⁴ / 0.01

            h = 0.0983  m

this is equal to h = 9.83 cm


Define friction. Prove that tangent of angle of friction is equal to coefficient
of friction.​

Answers

Answer:

Friction is the force that opposes movement between moving objects.

The angle at which one object starts to slip on the other is directly related to the coefficient. When the two objects are horizontal there is no frictional force. So, the coefficient of static friction is equal to the tangent of the angle at which the objects slide. A similar method can be used to measure μk.

Explanation:

Answer:

brainliest plsssssss

Explanation:

The resistance that one surface or object encounters when moving over another

14. After finishing her homework, Sue climbs up a 5.00 m high flight of stairs to her bedroom
Find the magnitude of Sue's weight
and how much
work Sue does in climbing the stairs if she
has a mass of 50.0 kg? (4.90 x 2 N, 2450J)

Answers

Explanation:

Given parameters:

Height  = 5m

Mass of Sue  = 50kg

Unknown:

Magnitude of Sue's weight  = ?

Work done by Sue = ?

Solution:

Weight is the vertical force exerted by a body in the presence of gravity.

Mathematically;

        W = mg

m is the mass

g is the acceleration due to gravity  = 9.8m/s²

  Weight  = 50 x 9.8  = 490N

Work done  = Force x distance = weight x height

 Work done  = 490 x 5 = 2450J

What happens to most of the light waves that strike a clear pane of glass? O A. absorption B. diffraction O C. reflection O D. transmission​

Answers

slight reflect but most goes through because glass is transparent

Most of the light waves that strike a clear pane of glass reflects. Details about reflection can be found below.

What is reflection?

Refection in physics is the property of a propagated wave being thrown back from a surface such as a mirror.

Mirror is an example of an object that could be hit by an incumbent wave, however, most of the light waves that hit the mirror surface gets reflected back.

Therefore, most of the light waves that strike a clear pane of glass reflects.

Learn more about refection at: https://brainly.com/question/15487308

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If at some point in time an object has zero velocity and zero acceleration, what does that mean about its motion at the next instant

Answers

Answer:

Explanation:

Usually, when an object possesses 0 velocity, then the object is expected to be at rest. But like the popular saying, there's always an exception to every rule. There exists cases in which an object isn't at rest, but possesses 0 speed or velocity. Since acceleration is the rate of change of velocity with time, the acceleration becomes negative, instead of positive.

Again, when the acceleration becomes zero, it means that the object isn't moving or it has no speed. And thus, the body is at rest. Every moving body as an acceleration, either positive, or negative. Zero acceleration means the object is at rest, and not moving at all.

Please leave a like if it helped you

At any point in time, when

when the acceleration becomes zero, it means that the object isn't moving or it has no speed. And thus, the body is at rest.

What is acceleration?

Acceleration is defined as the change of the velocity with the time. Acceleration is a vector quantity and is defined by both the magnitude and the direction

when the acceleration becomes zero, it means that the object isn't moving or it has no speed. And thus, the body is at rest. Every moving body as an acceleration, either positive, or negative. Zero acceleration means the object is at rest, and not moving at all.

Now If an object is moving with an acceleration that causes its speed to be reduced, there will be a moment in which it reaches v = 0, but this doesn't necessarily mean that the acceleration isn't acting anymore. If the object continues its movement with the same acceleration, it's velocity will become negative.

If you throw an object in the air with a certain velocity, it will move vertically, reducing its velocity in a 9,8  rate (which is the acceleration caused by gravity). At a certain point, the object will reach its maximum height, and will start to fall. In the exact moment that it reaches the maximum height, before it starts falling, its velocity is zero, but gravity is still acting on the object (this is the reason why it starts falling instead of just being stopped at that point). Therefore, at that point, the object has zero velocity but an acceleration of 9,8 .

To know more about acceleration follow

brainly.com/question/25749514

Q2. You push a crate up a ramp with a force of 10 N. Despite your pushing, the crate slides down the ramp 4 m. How much work did you do

Answers

Answer:

40 J

Explanation:

From the question given above, the following data were obtained:

Force (F) = 10 N

Distance (s) = 4 m

Workdone (Wd) =?

Work done is simply defined as the product of force and distance moved in the direction of the force. Mathematically, we can express the Workdone as:

Workdone = force × distance

Wd = F × s

With the above formula, we can obtain the workdone as follow:

Force (F) = 10 N

Distance (s) = 4 m

Workdone (Wd) =?

Wd = F × s

Wd = 10 × 4

Wd = 40 J

Thus, 40 J of work was done.

Help! Help!

___ are a primary way to discourage drinking and driving.
A. High prices for alcohol
B. Scare tactics
C. Laws

Answers

Answer:

Laws

Explanation:

Laws are a primary way discourage drinking and driving

A primary way to discourage drinking and driving is Law.

What is drinking and driving?

The person who takes in alcohol and then drives on the road. This is strictly prohibited.

Laws against the  'drinking and driving' will make people get scared of getting charged or sentenced to jail for some years. Lot of accidents have caused when there were no laws against the action.

Thus, Laws are a primary way to discourage drinking and driving.

Learn more about drinking and driving.

https://brainly.com/question/11317786

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A(n) 636 kg elevator starts from rest. It moves upward for 4.5 s with a constant acceleration until it reaches its cruising speed of 2.05 m/s. The acceleration of gravity is 9.8 m/s 2 . Find the average power delivered by the elevator motor during this period. Answer in units of kW.

Answers

Answer:

The average power delivered by the elevator motor during this period is 6.686 kW.

Explanation:

Given;

mass of the elevator, m = 636 kg

initial speed of the elevator, u = 0

time of motion, t = 4.5 s

final speed of the elevator, v = 2.05 m/s

The upward force of the elevator is calculated as;

F = m(a + g)

where;

m is mass of the elevator

a is the constant acceleration of the elevator

g is acceleration due to gravity = 9.8 m/s²

[tex]a = \frac{v-u}{t} \\\\a = \frac{2.05 -0}{4.5} \\\\a = 0.456 \ m/s^2[/tex]

F = (636)(0.456 + 9.8)

F = (636)(10.256)

F = 6522.816 N

The average power delivered by the elevator is calculated as;

[tex]P_{avg} = \frac{1}{2} (Fv)\\\\P_{avg} = \frac{1}{2} (6522.816 \ \times \ 2.05)\\\\P_{avg} = 6685.89 \ W\\\\P_{avg} = 6.68589 \ kW\\\\P_{avg} = 6.686 \ k W[/tex]

Therefore, the average power delivered by the elevator motor during this period is 6.686 kW.

how are hydrosphere, atmosphere, Biosphere, and Biosphere connected to one another

Answers

Explanation:

Such spheres are intimately connected. Many animals (biosphere), for example, migrate through to the sky, while groundwater (hydrosphere) also flows through the ground (lithosphere). The domains are actually so closely related that a shift in one globe always results in a shift in one or both of some other spheres.

which of the following is not a mechanical form of energy?
a. Nuclear
b. Kinetic
c. Spring potential
d. Gravitational potential ​

Answers

Answer:

The answer is Spring Potential

Explanation:

Because all the others are a mechanical form of energy

An automobile which set the world record for acceleration increase speed from rest to 96 km/h in 3.07 seconds what distance traveled by the time the final speed was achieved

Answers

Answer:

41.02m

Explanation:

Given parameters:

Initial velocity = 0m/s

Final velocity  = 96km/hr

Time taken  = 3.07s

Unknown:

Distance traveled by the time the final speed was achieved = ?

Solution:

To solve this problem, we first find the acceleration of the car;

     Acceleration  = [tex]\frac{v - u }{t}[/tex]

v is the final velocity

u is the initial velocity

t is the time taken

  Now convert the the final velocity to m/s;

          96km/hr to m/s;

               1 km/hr  = 0.278m/s

               96km/hr  = 96 x 0.278 = 26.7m/s

Now;

 Acceleration  = [tex]\frac{26.7 - 0}{3.07}[/tex]   = 8.69m/s²

So;

   v²  = u²  + 2as

v is the final velocity

u is the initial velocity

a is the acceleration

s is the distance

             26.7²  = 0²  + 2 x 8.69 x s

             712.89  = 17.38s

                  s  = 41.02m

please help thank you ​

Answers

YOUR QUERY :

which of the following statements BEST describes the difference between an atom and an ion ?

Answer:

well the correct answer is

d. An atom contains equal numbers of protons and electrons whereas an ion contains unequal numbers of protons and electrons .

Explanation:

A charged atom is known as an ion, well it can be negative as well as positive charge.

if atom has more protons than electrons then it get positively charged and known as cation

if the atom has more electrons that the number of protons then the atom get negatively charged and known as anion

A different bullet has a mass of 0.09 kg. Starting from rest, after its gun's trigger is pulled, a constant force acts on the bullet for the next 0.025 seconds until the bullet leaves the barrel of the gun with a speed of 1,346 m/s.

What force acts on this bullet?

Answers

The force acts on this bullet : 4.8456 N

Further explanation

Given

m=0.09 kg

Δt=0.025 s

vo=0(from rest)

vt=1.346 m/s

Required

Force

Solution

Impulse is a change in momentum

I=ΔP

F.Δt=m(vt-vo)

Input the value

F x 0.025 = 0.09(1.346-0)

F=4.8456 N

let's say you hypothetically ran over someone with your car, and they are now under your car in between the front wheels and the back wheels, right, and they're stuck as in can't breathe type stuck, right, do you keep driving so they can breathe or do you let them chill under your car?
just curious...​

Answers

question: is this actually hypothetical?

Explanation:

also just leave the car there go get some McDonald's or sum and come back and if they're still breathing then go ahead and move the car .

Answer:

the same thing the last guy said

The least count of stopwatch is 0.2s.The time of 20 oscillations of a pendulum was measured to be 25s.Find the percentage error in the measurement of time​

Answers

Answer:

0.8%

Explanation:

We are given;

Number of oscillations; n = 20

Time taken; t = 25 s

Formula for period of oscillation;

T = t/n = 25/20 = 1.25 s

We are told that the least count is 0.2 s. Thus, error is; ΔT = 0.2 s

percentage error in the measurement of time is given by;

(0.2/(20 × 1.25)) × 100% = 0.8%

Two identical plastic cups contain the same amount of water at two different temperatures, as shown to the left. Both cups are placed in a room at 25° Celsius. At the time cups were placed in the room, in which cup do the water molecules have higher average kinetic energy? ( Cup 1 © Cup 2​

Answers

Answer:

the molecules will begin to move slowly and will turn to ice

Explanation:

hope this was good or not not sure if am right but yeah

The metal wire is stretched so that its cross-section is still circular but its total length is now 10 meters. What is the resistance of the wire after stretching

Answers

I don’t know I think about 20 meters but I’m probably wrong I just need to do this so someone can answer my question
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