Answer:
The temperature of silver at this given resistivity is 2971.1 ⁰C
Explanation:
The resistivity of silver is calculated as follows;
![R_t = R_o[1 + \alpha(T-T_o)]\\\\](https://tex.z-dn.net/?f=R_t%20%3D%20R_o%5B1%20%2B%20%5Calpha%28T-T_o%29%5D%5C%5C%5C%5C)
where;
Rt is the resistivity of silver at the given temperature
Ro is the resistivity of silver at room temperature
α is the temperature coefficient of resistance
To is the room temperature
T is the temperature at which the resistivity of silver will be two times the resistivity of iron at room temperature
![R_t = R_o[1 + \alpha(T-T_o)]\\\\\R_t = 1.59*10^{-8}[1 + 0.0038(T-20)]](https://tex.z-dn.net/?f=R_t%20%3D%20R_o%5B1%20%2B%20%5Calpha%28T-T_o%29%5D%5C%5C%5C%5C%5CR_t%20%3D%201.59%2A10%5E%7B-8%7D%5B1%20%2B%200.0038%28T-20%29%5D)
Resistivity of iron at room temperature = 9.71 x 10⁻⁸ ohm.m
When silver's resistivity becomes 2 times the resistivity of iron, we will have the following equations;
![R_t,_{silver} = 2R_o,_{iron}\\\\1.59*10^{-8}[1 + 0.0038(T-20)] =(2 *9.71*10^{-8})\\\\\ \ (divide \ through \ by \ 1.59*10^{-8})\\\\1 + 0.0038(T-20) = 12.214\\\\1 + 0.0038T - 0.076 = 12.214\\\\0.0038T +0.924 = 12.214\\\\0.0038T = 12.214 - 0.924\\\\0.0038T = 11.29\\\\T = \frac{11.29}{0.0038} \\\\T = 2971.1 \ ^0C](https://tex.z-dn.net/?f=R_t%2C_%7Bsilver%7D%20%3D%202R_o%2C_%7Biron%7D%5C%5C%5C%5C1.59%2A10%5E%7B-8%7D%5B1%20%2B%200.0038%28T-20%29%5D%20%3D%282%20%2A9.71%2A10%5E%7B-8%7D%29%5C%5C%5C%5C%5C%20%5C%20%28divide%20%5C%20through%20%5C%20by%20%5C%201.59%2A10%5E%7B-8%7D%29%5C%5C%5C%5C1%20%2B%200.0038%28T-20%29%20%3D%2012.214%5C%5C%5C%5C1%20%2B%200.0038T%20-%200.076%20%3D%2012.214%5C%5C%5C%5C0.0038T%20%2B0.924%20%3D%2012.214%5C%5C%5C%5C0.0038T%20%20%3D%2012.214%20-%200.924%5C%5C%5C%5C0.0038T%20%3D%2011.29%5C%5C%5C%5CT%20%3D%20%5Cfrac%7B11.29%7D%7B0.0038%7D%20%5C%5C%5C%5CT%20%3D%202971.1%20%5C%20%5E0C)
Therefore, the temperature of silver at this given resistivity is 2971.1 ⁰C
Answer:
b. The side the boy is sitting on will tilt downward
Explanation:
Initially, the seesaw is balanced because the torque exerted by the boy is equal to the torque exerted by the girl:

where
Wb is the weight of the boy
db is the distance of the boy from the pivot
Wg is the weight of the girl
dg is the distance of the girl from the pivot
When the boy moves backward, the distance of the boy from the pivot (
increases, therefore the torques are no longer balanced: the torque exerted by the boy will be larger, and therefore the side of the boy will tilt downward.
Answer:
mistakes I guess lol don't take serious