Steam at 100°c is condensed into a 38.0 g aluminum calorimeter cup containing 280 g of water at 25.0°c. determine the amount of steam (in g) needed for the system to reach a final temperature of 40.0°c. the specific heat of aluminum is 900 j/(kg · °c).

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?