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Ghella [55]
3 years ago
14

Newton's law of cooling states that the temperature of an object changes at a rate proportional to the difference between its te

mperature 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.
Physics
1 answer:
schepotkina [342]3 years ago
4 0

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.

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What do you mean by kinetic energy and potential energy ?
Verizon [17]

  • Kinetic Energy of an object is the measure of the work an object can do by virtue of its motions..

  • Formula - KE = 1/2 mv^2

  • Where KE is the kinetic energy, m is the body’s mass, and v is the body’s velocity.

  • Potential energy is the stored energy in any object or system by virtue of its position or arrangement of parts..

  • Formula - W = mgh

Where,

. m is the mass in kilograms

. g is the acceleration due to gravity

. h is the height in meters

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4 0
2 years ago
On a typical clear day, the atmospheric electric field points downward and has a magnitude of approximately 103 N/C. Compare the
Nina [5.8K]

Answer:

a) FE = 0.764FG

b) a = 2.30 m/s^2

Explanation:

a) To compare the gravitational and electric force over the particle you calculate the following ratio:

\frac{F_E}{F_G}=\frac{qE}{mg}              (1)

FE: electric force

FG: gravitational force

q: charge of the particle = 1.6*10^-19 C

g: gravitational acceleration = 9.8 m/s^2

E: electric field = 103N/C

m: mass of the particle = 2.2*10^-15 g = 2.2*10^-18 kg

You replace the values of all parameters in the equation (1):

\frac{F_E}{F_G}=\frac{(1.6*10^{-19}C)(103N/C)}{(2.2*10^{-18}kg)(9.8m/s^2)}\\\\\frac{F_E}{F_G}=0.764

Then, the gravitational force is 0.764 times the electric force on the particle

b)

The acceleration of the particle is obtained by using the second Newton law:

F_E-F_G=ma\\\\a=\frac{qE-mg}{m}

you replace the values of all variables:

a=\frac{(1.6*10^{-19}C)(103N/C)-(2.2*10^{-18}kg)(9.8m/s^2)}{2.2*10^{-18}kg}\\\\a=-2.30\frac{m}{s^2}

hence, the acceleration of the particle is 2.30m/s^2, the minus sign means that the particle moves downward.

7 0
3 years ago
A 22.0 nF capacitor is connected across an AC generator that produces a peak voltage of 5.80 V. part a
mariarad [96]

Answer:

Explanation:

Impedence of the circuit = peak voltage / peak current

= 5.8 / 51 x 10⁻³

= 113.725 ohm.

1 / wC =113.725

w = 1 / (113.725 x 22 x 10⁻⁹ )

= 10⁹ / 2.5 x 10³

=10⁶ / 2.5

40 x 10⁴

frequency n = 40 x 10⁴ / 2 x 3.14

6.37 x 10⁴ Hz.

b ) charge on the capacitor = 1 C

V = Q / C

= Charge / capacitor

= 1 / 22 x 10⁻⁹

4.54 x 10⁷ V.

4 0
3 years ago
7. You start to walk toward the east towards home at a constant speed of 4 km/hr. At the same time, Someone else leaves your hom
amm1812

A) position time graph for both is shown

here one of the graph is of lesser slope which means it is moving with less speed while other have larger slope which shows larger speed

At one point they intersects which is the point where they both will meet

B) Let the two will meet after time "t"

now we can say that

if they both will meet after time "t"

then the total distance moved by you and other person will be same as the distance between you and home

so it is given as

v_1t + v_2t = d

4*t + 28*t = 3.2 km

t = \frac{3.2}{32} = 0.1 hr

so they will meet after t = 6 min

so from position time graph we can see that two will meet after t = 6 min where at this position two graphs will intersect


4 0
4 years ago
Physicists at CERN study the conditions present during the big bang by using machines to do what?
VARVARA [1.3K]

Answer:

The Answer is gonna be According D.separate atoms from their electrons

8 0
3 years ago
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