During a 40-mile trip, marla traveled at an average speed of x miles per hour for the first y miles of the trip and at an average speed of 1.25x miles per hour for the last 40 – y miles of the trip. the time that marla took to travel the 40 miles was what percent of the time it would have taken her if she had traveled at an average speed of x miles per hour for the entire trip?

Water at room temperature of 20.0°c is poured into an aluminum cylinder which has graduation markings etched on the inside. the reading in the graduations is 300.0 cc. the cylinder with the water in it is then immersed in a constant temperature bath at a temperature of 100°c. what is the reading for the level of water on the graduations of the cylinder after the water and the cylinder reach thermal equilibrium with the bath? the volume coefficient of expansion of water is 2.07 x 10^-4 k-1, and the linear coefficient of expansion of aluminum is 23.0 x 10^-6 k-1. a) 305.0 cc b) 304.0 cc c) 303.5 cc d) 303.3 cc e) 304.5 cc

Sobre transformações cíclicas, são feitas algumas afirmações, determine quais estão corretas. i – a variação de energia interna em uma transformação cíclica é nula; ii – o trabalho, em uma transformação cíclica, é sempre positivo; iii – ao completar um ciclo, o gás tem a mesma temperatura com a qual começou a transformação; iv – uma transformação cíclica é, obrigatoriamente, composta de transformações conhecidas, como adiabática, isocórica, etc: a) i e iii b) i e ii c) ii e iii d) i e iv e) iii e iv

This is important 1. what happens to the speed of molecules in water vapor when it condenses to form a liquid? (2 points) the molecules slow down. the molecules speed up. the molecules slow down and then speed up. the molecules speed up and then slow down. 2. how might human activities change to compensate for a decrease in water supplies? (2 points) humans might build a factory. humans might build drainage systems. humans might extract more water from the ground. human behavior does not change because of the water cycle. i'll be grateful if anyone can answer these 2 questions !