Một học sinh thả 300g chì ở nhiệt độ ở 1000C vào 250g nước ở 58,50C làm cho nước nóng lên đến 600C. Cho biết nhiệt dung riêng của nước c1=4 190J/kg. K a) Hỏi nhiệt độ của chì ngay khi có cân bằng nhiệt? b) Tính nhiệt lượng nước thu vào. c) Tính nhiệt dung riêng của chì. Coi như chỉ có chì và nước trao đổi nhiệt cho nhau.

Laboratory experiments, observational field studies, and model-building are all examples of different forms of scientific investigations.  in what way do laboratory experiments primarily differ from other forms of scientific investigations?   a.  a laboratory experiment is the only accepted form of investigation within the scientific community.  b.  studies about how things behave in nature or studies involving very large objects are best answered through laboratory experiments.  c.  laboratory experiments involve the identification and control of variables.  d.  data can only be generated through laboratory experiments, not other forms of investigation.

Asuppose a suitcase has a mass of (m) 30 kg and a net force (n) of 10 kg*m/s. what is the acceleration rate of the suitcasein m/s? show your work to support your answer.

Unpolarized light falls on two polarizer sheets whose transmission axes are at right angles. a third polarizer is placed between the first two so that its axis makes a 52-degree angle with the axis of the first polarizer. a) what fraction of the incident light intensity is transmitted through the first polaroid? b) what fraction of the incident light intensity is transmitted through the second polaroid? c) what is the angle of polarization of the light that enters the third polaroid? d) what fraction of the incident light intensity is transmitted through the third polaroid. e) what happens if the middle polaroid is removed?