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koban [17]
3 years ago
8

A loaf of bread is removed from an oven at 350° F and cooled in a room whose temperature is 70° F. If the bread cools to 210° F

in 20 minutes, how much longer will it take the bread to cool to 185° F.
Physics
1 answer:
jasenka [17]3 years ago
7 0

Answer:

The bread will take 216.40 minutes to cool to 185°F

Explanation: Newton law of cooling

states that the rate of cooling of an object is inversely proportional to the difference of temperatures between the object and its surroundings i.e. dTdt=−kT, where t is the time taken and T is the difference of the temperatures between the object and its surroundings.

This gives us T as a function of t and is given by T(t)=ce−kt.

T(0)= Ce^-kt

C=35₩F- 185F= 165F

T(20) = 165×e^-20k=(350-70)

T(20)= e^-20k =280/165

-20k= ln(280/165)

-20k= ln(1.697)

-20k= 0.5289

K= 0.5289/20

K= 0.0264

If it cools at 185F in t minutes

165e^-0.0264×t=0.5

e^-0.0264t= 0.5/165

-0.0264t= on 3.03×10^-3

-0.0264t= -5.7129

t= 5.7129/0.0264

t=216.40minutes

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Answer with Explanation:

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Frequency=\frac{1200}{60}=20 Hz

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Angular velocity=\omega=2\pi f

Angular velocity=2\times \frac{22}{7}\times 20=125.7 rad/s

b.We have to find the linear speed of its tip at this  angular velocity if the plane is stationary on the tarmac.

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3 years ago
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Answer:

4.25 J

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KE=\dfrac{1}{2}mv^2

KE=\dfrac{1}{2}\times 0.011\times 29^2

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Answer:

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Explanation:

In order to calculate the magnitude and direction of the magnetic field, you take into account the following equation for the magnetic force on the proton:

\vec{F_B}=q\vec{v}\ X\ \vec{B}       (1)

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

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FB: magnetic force on the proton = 1.6*10^-13N

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To obtain the magnitude of the magnetic field you use:

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The magnitude of the magnetic field is 1.01T and its direction is in the negative x direction

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the gas that escaped from the mixture contained the missing weight

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