Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its temperature and that of its surroundings. Suppose that the temperature of a cup of coffee obeys Newton's law of cooling. If the coffee has a temperature of 185 degrees Fahrenheit when freshly poured, and 3 minutes later has cooled to 172 degrees in a room at 78 degrees, determine when the coffee reaches a temperature of 147 degrees.

Answers

Answer 1

Answer:

6.77 minutes

Explanation:

172 degree - 78 degree = (185 degree - 78 degree)e−2 k

=> 94 = 107

e−2 k => 94 ÷ 107

k => ln (94÷107) / 2

147 - 78 = (185 - 78)e ^[ln (94÷107) / 2]

=> 69 = 107 e^ [ln (94÷107) / 2]

e^[ln (94÷107) / 2] =69 ÷ 107

=> t = [ln (69 ÷ 107)] ÷ [ln (94÷107) / 2]

t=> -0.4387 ÷ -0.0648

t => 6.77 minutes.

Therefore, the final answer to the question is 6.77 minutes.


Related Questions

Riders in an amusement park ride shaped like a Viking ship hung from a large pivot are rotated back and forth like a rigid pendulum. At each end of the swing the ship hangs motionless for a moment before the ship swings down under the influence of gravity. Assume that this motionless point occurs when the bar connecting the pivot point and the ship is horizontal.

Required:
a. Assuming negligible friction, find the speed of the riders at the bottom of its arc, given the system's center of mass travels in an arc having a radius of 14.0 m and the riders are near the center of mass.
b. What is the centripetal acceleration at the bottom of the arc?
c. Draw a free body diagram of the forces acting on a rider at the bottom of the arc.
d. Find the force exerted by the ride on a 60.0 kg rider and compare it to her weight.
e. Discuss whether the answer seems reasonable.

Answers

Answer:

a)  v = 16.57 m / s, b)  a = 19.6 m / s², d)    N = 1.76 10³ N,     N / W = 3

Explanation:

This exercise looks interesting, but I think you have some problem with the writing, the questions seem a bit disconnected from the initial text.

Let's answer the questions.

a) For this part we can use energy considerations.

Starting point. The upper part of the trajectory indicates that the arm is horizontally

          Em₀ = U = m g h

in this case h = r

Final point. For lower of the trajectory

          Em_f = K = ½ m v²

as they indicate that there is no friction

         Em₀ = em_f

         mgh = ½ m v²

         v = [tex]\sqrt{2gh}[/tex]

let's calculate

        v = [tex]\sqrt{2 \ 9.8 \ 14.0}[/tex]

         v = 16.57 m / s

b) the centripetal acceleration has the formula

           a = v² / r

           a = 16.57² / 14.0

           a = 19.6 m / s²

c) see attached where the diagram is

where N is the normal and w the weight

d) let's use Newton's second law

               N-W = m a

               N - mg = m ar

               N = m (g + a)

let's calculate

               N = 60.0 (9.8 + 19.6)

               N = 1.76 10³ N

the relationship with weight is

              N / W = 1.76 10³/( 60 9.8)

              N / W = 3

normal is three times greater than body weight

e) the answer is reasonable since by Newton's first law the body must continue in a straight line, therefore to change its trajectory a force must be applied to deflect it

a potted plant falls from a window sill and is gaining speed. which one of the following statements is true of the plant?

a) its kinetic energy is constant
b) its kinetic energy is increasing
c) its kinetic energy is decreasing​

Answers

It’s kinetic energy is increasing

A car is travelling at 15 m/s on a horizontal road and stopped after 4 s. The coefficient of kinetic friction between the tires and road is:​

Answers

Answer:

Fr,= umg

umg= ma

a= v/t

umg= mv/t

u= v/gt= 0.38

18. Write conversion factors (as ratios) for the number of:
(a) yards in 1 meter
(b) liters in 1 liquid quart
(c) pounds in 1 kilogram

Answers

Answer:

Conversion tables show:

1 m = 1.09361 yds

1 Lit = .26418 gal = 1.05672 qt     or 1 qt = .944632 Lit

1 lb = .45359 kg = 2.2046 Lbs / Kg

So X yds = X  m * 1.09361 yds / m = 1.09361 * X yds

Likewise X Lit  = X  qt  / 1.05672 qt/ Lit = X / 1.05672 Lit = .94632  X Lit

So X  Lbs =  X kg * 2.2046 Lbs / Kg = 2.2046 Lbs

HELP PLS
21. Inferring The charged particle on the left is a proton. What is the charged
particle on the right? How do you know?

Answers

If the field is in a vacuum, the magnetic field is the dominant factor determining the motion. Since the magnetic force is perpendicular to the direction of travel, a charged particle follows a curved path in a magnetic field. The particle continues to follow this curved path until it forms a complete circle. Another way to look at this is that the magnetic force is always perpendicular to velocity, so that it does no work on the charged particle. The particle’s kinetic energy and speed thus remain constant. The direction of motion is affected but not the speed.

A negatively charged particle moves in the plane of the paper in a region where the magnetic field is perpendicular to the paper (represented by the small × ’s—like the tails of arrows). The magnetic force is perpendicular to the velocity, so velocity changes in direction but not magnitude. The result is uniform circular motion.

I think it would be a electron
I’m not sure if my explanation is correct but I’m gonna say it’s bc they attract ik it had to be right it’s just my explanation that’s wrong

why is the meteor shower is best observed after midnight?​

Answers

Answer:

At dawn your location on earth is pointed straight in the direction of the Earth's travel in its orbit.  Between midnight and dawn you are moving head-on through the location of the meteors in space, which means that you will, on average, observe more of them.

- public.nrao.edu

Explanation:

hope this helps

Two point masses are held in place a distance d apart. Another point mass M is midway between them. M is then displaced a small distance x perpendicular to the line connecting the two fixed masses and released.

a. Show that the magnitude of the net gravitational force on M due to the fixed masses is guven approximately by Fnet = 16GmM/d^3x if x ≪ d.
b. What would the period be if m = 100kg and d = 25.0cm?
c. Will M oscillate if it is displaced from the center a small distance x toward either of the fixed masses?.

Answers

THAT LINK IS A VIRUS NEVER GO TO A LINK and if you go to “goggle” you should see a camera icon and take a picture of the question and get the answer there

Imagine you have three flashlights. One has a blue light, one has a green light and
one is red. If you were to shine each of those lights in the same spot, what color do
you think you would see? Explain.

Answers

We would see the color white.

Imagine you have three flashlights. One has a blue light, one has a green light and one is red. If you were to shine each of those lights in the same spot, I think i would see white color.

What is the visible spectrum?

At one end of the electromagnetic wave line, which has the group of the visible spectrum. This has been referred to as the visible light of the spectrum. The visible light with the shortest of the wavelength has the blue light and the one with the longest has the red light.

The primary colors of the light has been the spectrum are red, blue, and green. The combination of these colors will form other as well as the colors which has been referred to as the secondary colors. The combination of the beam of the red light and the beam of green light will form yellow color.

Therefore, Imagine you have three flashlights. One has a blue light, one has a green light and one is red. If you were to shine each of those lights in the same spot, I think i would see white color.

Learn more about flashlights on:

https://brainly.com/question/25780677

#SPJ2

Lava from a volcano becomes solid as a result of
A. cooling
B. heating.
C. evaporating.
D. condensing.
E. melting.

Answers

Answer:

B. heating.

Explanation:

Answer:

A. Cooling

Explanation:

Because when Lava cools down, it hardens and becomes a solid, and is less hotter.

Please help me !!!!!!!

Answers

Answer:  I believe that it is 35 Joules.

Explanation:

100 - 65 = 35

:)

Which of the following describes an electric conductor?

Answers

A substance which allows the un-interrupted flow of electric current is called an electric conductor
An electric conductor conducts (transports or allows to pass) any electricity with facility.

Roger drives his car at a constant speed of 80 km/hr. How far can he travel in 2 hrs. and 30 minutes?

Answers

Answer:

200 km/hr

Explanation:

Since he goes 80km per hour, multiply this by 2.5 or two and a half hours.

80 x 2.5 = 200 km/hr.

How can parents help children to gain friends?

Answers

Answer:

You could try finding a familiar peer to join the activity with your child. Or ask your child who their friends are at school, or what they look for in a friend at school.

Answer:

Let the parents their Children to play outside

Explanation:

I HOPE I HELP YOU

how is a trench and a tsunami related? 6-8 sentences

Answers

Answer: A tsunami is a very long-wavelength wave of water that is generated by sudden displacement of the seafloor or disruption of any body of standing water.  Tsunami are sometimes called "seismic sea waves", although they can be generated by mechanisms other than earthquakes.  Tsunami have also been called "tidal waves", but this term should not be used because they are not in any way related to the tides of the Earth.  Because tsunami occur suddenly, often without warning, they are extremely dangerous to coastal communities. Ocean trenches are steep depressions in the deepest parts of the ocean [where old ocean crust from one tectonic plate is pushed beneath another plate, raising mountains, causing earthquakes, and forming volcanoes on the seafloor and on land.  

Explanation:

Consider the path of a comet orbiting a star, the system of the comet plus the star. Which of the following statements are correct? Select all that are True. 1) As the comet slows down, the kinetic energy of the system decreases. 2) As the comet's kinetic energy increases, the gravitational potential energy of the system also increases. 3) External work must be done on the system to speed up the comet. 4) As the kinetic energy of the system increases, the gravitational potential energy of the system decreases. 5) As the comet slows down, energy is lost from the system.

Answers

Answer:

True  1, 4

False 2, 3, 5

Explanation:

The system is formed by the Sun that is fixed at a point (focus of movement) and the comet that rotates around in styptic orbits. The only force involved is the force of attraction between the two bodies, if we write the energy of the system

         Em = K + U

         Em = ½ m v2 + G m Ms / r2

where m is the mass of the comet, Ms the mass of the Sun and r the distance between them.

This system is isolated so the energy is conserved throughout the movement, it only transforms from kinetic to gravitational potential.

Let's review the different claims;

1) True. The speed of the comet determines its kinetic energy, so when decreasing the speed decreases the kinetic energy, there is also a decrease due to the lost mass

2) False. The total energy is constant, so if the kinetic energy increases, the power energy must decrease

3) False. The comet's speed changes are due to changes in gravitational energy, so no external work is needed to change the speed.

4) True. Correct because the sum of the two must be constant

5) False. When the comet loses speed, the energy increases, the power would gravitate, so there is no loss of energy, we are ignoring the loss of mass of the comet.

Please help !!!!!!!!!!!!

Answers

Answer:

152 Volts

Explanation:

First, the Resistors are in series. So, the net resistance, R = 3 + 4 +3 + 4 +5

= 19 ohms

Using, V = IR;

V (the needed P.D) = 8 x 19 = 152 Volts

will be needed to successfully transport 8 amps of current round the circuit

Answer:

4q

Explanation:

wait nvm i dont know

A vibrating mass of 300 kg mounted on a massless support by a spring of stiffness 40,000 N>m and a damper of unknown damping coefficient is observed to vibrate with a 10-mm amplitude while the support vibration has a maximum amplitude of only 2.5 mm (at resonance). Calculate the damping constant and the amplitude of the force on the base.

Answers

Answer:

400 N

Explanation:

[tex]\text { Given: } m=300 \mathrm{~kg}, k=40,000 \mathrm{~N} / \mathrm{m}, \omega_{b}=\omega_{n}(r=1), X=10 \mathrm{~mm}, Y=2.5 \mathrm{~mm}[/tex] .

Find damping constant

[tex] \frac{X}{Y}=\left[\frac{1+(2 \zeta r)^{2}}{\left[\left(1-r^{2}\right)^{2}+(2 \zeta r)^{2}\right.}\right]^{1 / 2} \\ \left.\frac{10}{2.5}=\frac{\left\lceil 1+4\zeta^{2}\right]^{1 / 2}}{4 \zeta^{2}}\right] \\ 16=\frac{1+4 \zeta^{-2}}{4 \zeta^{2}} \\ \zeta^{2}=\frac{1}{60}=\frac{c^{2}}{4 k m} \\ c=\sqrt{\frac{4(40,000)(300)}{60}} \\ c=894.4 \mathrm{~kg} / \mathrm{s}[/tex]

Amplitude of force on base:

[tex]F_{T}=k Y r^{2}\left[\frac{1+(2 \zeta r)^{2}}{\left(1-r^{2}\right)^{2}+(2 \zeta r)^{2}}\right]^{1 / 2}[/tex]

substituting the values in above formula we get

F_T = 400 N

D
If you increase the
frequency of a
wave, what
happens to the
speed?
G
A. It decreases.
B. It stays the same.
C. It increases.
D. It can increase or decrease.

Answers

Answer:

D

Explanation:

I think you got it right

The answer Is D!! Hope this helps

Can someone please help me with this !!!!

Answers

Answer:

I'm not sure but I think it's 4.5 v

Which of the following is an example of predation?

Answers

A. Owl is looking and attacking

Answer:

an owl hunts, catches, and consumes a field mouse for energy

Explanation:

Cartesian coordinate system is used for?​

Answers

Answer:

sorry not sure but i can try help with telling you this...

Explanation:

alls you havs to do is ask the internet and it will tell you

An amateur blacksmith wants to cool off a 42kg glowing piece of iron, specific heat 470and decides to toss it into a 5.0 kg iron bucket with 10.0 kg of room temperature(23 C) water in it. To his surprise the water completely evaporates away (meaning once it vaporizes it is no longer part of the system) and after some time he goes to pick up the bucket but finds that the bucket is at 150 C.

Required:
What was the initial temperature of the glowing piece of iron?

Answers

Answer:

The right approach is "1479°C".

Explanation:

The given values are:

Mass of iron piece,

[tex]m_p=42 \ kg[/tex]

Mass of iron bucket,

[tex]m_I=5 \ kg[/tex]

Mass of water,

[tex]m_w=10 \ kg[/tex]

Iron's specific heat,

[tex]C_I=470 \ J/Kg^{\circ}C[/tex]

Water's specific heat,

[tex]C_w=4186 \ J/Kg^{\circ}C[/tex]

Initial temperature,

[tex]t_I=23^{\circ}C[/tex]

Final equilibrium temperature,

[tex]T=150^{\circ}C[/tex]

Latent heat,

[tex]L_v=2260\times 10^3 \ J/Kg[/tex]

As we know,

The heat lost by the glowing piece of iron will be equal to the heat gain by the iron bucket as well as water, then

⇒ [tex]m_IC_I \Delta T=m_wC_w(100-23)+m_wL_v+m_bC_I(150-23)[/tex]

On substituting the given values, we get

⇒ [tex]42\times 420\times \Delta T=10\times 4186(100-23)+10(2260\times 10^3)+5\times 420(150-23)[/tex]

⇒ [tex]17640 \Delta T=3.22\times 10^6+2.26\times 10^7+2.667\times 10^5[/tex]

⇒          [tex]\Delta T=\frac{2.60867\times 10^7}{17640}[/tex]

⇒          [tex]\Delta T=1479^{\circ}C[/tex]

If the distance doubles, what happens to the force?
a. Reduced by half
b. Reduced by 1/4
c. Stays the same
d. Quadruples

Answers

i think that it is D

What is a energy transformation when using a microwave to make popcorn?

Answers

Answer:

Radiation

Explanation:

Radiant energy

Explanation:

Radiant energy is transformed into thermal energy as the popcorn kernels absorb the microwaves. This causes the kernels to become hot and pop. Electric energy is transferred from the electrical outlet to the microwave.

What speed must a 600 kg car have in order to have the same momentum as a 1200 kg truck traveling at a velocity of 10 m/s to the west? 5 m/s west B 20 mls west 5 m/s east 20 m/s east

A) 5m/s west
B) 20m/s west
C) 5m/s east
D) 20m/s east

Answers

Answer:

20 m/s

Explanation:

Unless otherwise stated, all objects are located near the Earth's surface, where g = 9.80 m/s2 .
A force acts on a 1.5 kg , mass, giving it an acceleration of 3.0 m/s2 .
1. If the same force acts on a 3.0 kg mass, what acceleration would be produced?
2. What is the magnitude of the force?

Answers

Answer:

1) 1.5 m/s^2

2) 4.5 N

Explanation:

From Newton's Second Law of motion, we know

[tex]F=m*a[/tex]

Which states that to calculate the force acting on an object, you multiply its mass and acceleration.

So, we know an object of mass 1.5 kg has an acceleration of 3 m/s^2, then

[tex]F=m*a=1.5*3=4.5[/tex]

A force of 4.5 N is acting on the object.

If a force of 4.5 N acts on a mass of 3kg we have

[tex]a=\frac{F}{m}=\frac{4.5}{3}=1.5[/tex]

So, it would give it an acceleration of 1.5 m/s^2.

Can I please have help

Answers

Answer:

it will usually increase

Explanation:

potato

What is energy transfer in a car crash

Answers

Force energy- kinetic energy

Answer:

Kinetic and thermal

Explanation:

Kinetic because a moving car is transferring movement energy into the other one. Thermal because, in a car crash, the touching surfaces of both cars friction and that produces heat.

There are two main types of collisions that you will study: elastic and perfectly inelastic. In an elastic collision, kinetic energy is conserved. In a perfectly inelastic collision, the particles stick together and thus retain the same velocity after the collision.

a. True
b. False

Answers

Answer:

The first part is right (KE is conserved in an elastic collision).

The second part of the  statement is false,.

Since momentum is conserved, let moving mass m strike stationary mass M:

m v = (m + M) V   where m v is the momentum in

Obviously, v does not equal V.

Compare and contrast the solar eclipse seen in this video to a lunar eclipse.

Answers

Answer: sadly, I can’t see the video. However, a lunar eclipse happens when the moon is hidden by the earth’s shadow. A solar eclipse occurs when the moon casts a shadow on the earth.

Explanation: I’m not completely sure if this is what you were looking for, but I hope it helps anyway.

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