Question

Please I need answers to these questions, thanks.

brass ball gets so that it gets stuck in the ring. I've measured a similar piece of equipment. At room temperature (23 °C) the diameter of the ball is 1.90 cm and the inner diameter of the ring is 1.92 cm. How hot does the ball have to get in order for the ball to just get stuck? Hint: think of the diameter of the ball as a linear dimension, and find out how much bigger (linear expansion) the diameter would have to be so that it's just bigger than the inner diameter of the ring. You'l have to look up the coefficient of linear expansion of brass 2. A 200-g aluminum block is cooled in liquid nitrogen until it reaches a temperature of-190°C. It is then removed and placed into an insulated cup containing 100-g of water at 15.0°C. What is the equilibrium temperature of this system? If the answer is 0°C, find out how much of the water has frozen These questions are conceptual, and worth 5 points each. They are not graded with the rubric 1. If you add a little hot tea to ice water at 0 °C, the mixture will end up at 0 °C so long as some ice remains. Where does the tea's extra thermal energy go? 2. If you try to cook vegetables in 100 °C air, it takes a long time. But if you cook those same vegetables in 100 °C steam, they cook quickly. Why does the steam transfer so much more heat to the vegetables? 3. Why are concrete sidewalks divided into individual squares rather than being left as continuous concrete strips?

Answer 1

For conceptual problems

1. Tea's extra thermal energy is used up in melting the ice. This is called latent heat, where in the state of matter changes without change in temperature.

2. This is because the latent heat of vaporization of steam is 1760 times greater than that of hot water.

3. This is to avoid cracking of walls due to expansion in summers.