問PHY 2005 CE MC Q.6 AND Q.8－hzb53jl55v的部落格

標題:

問PHY 2005 CE MC Q.6 AND Q.8

發問:

問PHY 2005 CE MC Q.6 AND Q.8 可唔可以解釋下個答案問黎?

最佳解答:

Q6) A: Velocity is continuously changing since the direction of Edmund's motion is changing. B: K.E. is constant by the equation KE = (1/2)mv2 where v is counted for magnitude only. C: Potential energy is changing since the Edmund's height above the ground is changing. D: Total mechanical energy = Poteitial energy + KE, so it is also changing according to the deductions above. Ans = B. Q8) A: If the tile is a better insulator of heat, then it will not draw heat energy away as fast as the carpet and hence it is not felt as cold as the carpet when touched. B: Since they are in the same room, they are of the same temperature. C: If the tile has a lower specific heat capacity, less heat energy will be needed to warm it up than the carpet and hence it will not draw as much heat energy as the carpet. D: Tile is in fact a better heat conductor than carpet. Therefore heat energy is drawn away from her foot more quickly than the carpet and hence the foot on it feels cooler. Ans = D