Answer:
It's 1.0000042 times longer in summer than in winter. It represents a 1.6 centimeters difference between seasons.
Explanation:
The linear coefficient of thermal expansion for steel is about 
. From the equation of linear thermal expansion, we have:
Taking the winter day as the initial, and the summer day as the final, we can take the relationship between them:
![L_{summer}=L_{winter}[1+(1.2*10^{-7}\°C^{-1})(30\°C+5\°C)]\\\\L_{summer}=(1.0000042)L_{winter}](https://tex.z-dn.net/?f=L_%7Bsummer%7D%3DL_%7Bwinter%7D%5B1%2B%281.2%2A10%5E%7B-7%7D%5C%C2%B0C%5E%7B-1%7D%29%2830%5C%C2%B0C%2B5%5C%C2%B0C%29%5D%5C%5C%5C%5CL_%7Bsummer%7D%3D%281.0000042%29L_%7Bwinter%7D)
It means that the bridge is 1.0000042 times longer in summer than in winter. If we multiply it by the length of the bridge, we obtain that the difference is of about 1.6 centimeters between the two seasons.
Answer:
Explanation:
i )
In a conservative field like gravitational field , loss of potential energy or work done , depends upon the initial and final point and not the manner in which 2 nd point has been reached . Since the initial and final point is same in both the cases of straight and curved path , final velocity will remain same for both of them .
Hence , due to increased mass of larger child , his kinetic energy will be greater .
ii ) Since the initial and final point is same in both the cases of straight and curved path , final velocity will remain same for both of them .
iii ) Smaller child undergo free fall , therefore , he will fall with acceleration g . The larger child falls on curved path . So , he will have only a component of
vertical g at any moment . hence average acceleration will be less.
7) c
opposite charges attract, equal charges repell
8) c
Followed from equation
9) d
Same reason as under 7
