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3 years ago

A metal rod is 25.000 cm long at 25.0 degrees Celsius. When heated to 102.0

Physics

1 answer:

ser-zykov [4K]3 years ago

4 0

Answer:

The coefficient of linear expansion $\alpha =2.8\times 10^-5$ \°C

Explanation:

Given initial temperature $t_1=25$ °C

And final temperature $t_2=102$ °C

Initial length $l_1=25.000\ cm$

Final length $l_2=25.054\ cm$

We have to find the coefficient of linear expansion

The coefficient of linear expansion is defined as the change in length per unit original length divide by the change in temperature.

$l_2=l_1(1+\alpha (t_2-t_1))\\l_2-l_1=\alpha l_1(t_2-t_1)\\25.054-25.000=25.000(\alpha (102-25))\\0.054=\alpha\times 25(77)\\0.054=\alpha\times1925\\\alpha =\frac{0.054}{1925}=0.000028\C\\\alpha =2.8\times 10^-5$

So, $\alpha =2.8\times 10^-5$ \°C

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Klio2033 [76]

Answer:

its speed will be less than V

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K = U

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K = U

I' = new rotational inertia of drum and balls, ω' = new angular speed of drum and balls

With its new speed is now V' at the end of d,

1/2mV'² + 1/2I'ω'² = mgd

1/2mV'² = mgd - 1/2I'ω'²

V² = [2(mgd - 1/2I'ω'²)/m]

V' = √[2(mgd - 1/2I'ω'²)/m]

Since I' and ω' increase, the rotational kinetic energy of the drum and balls (1/2I'ω'²) increases. Thus, the difference (mgd - 1/2I'ω'²) < (mgd - 1/2Iω²) which implies that the kinetic energy of the box decreases. Hence, since its kinetic energy decreases, its speed V' also decreases.

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