You and your family take a trip to see your aunt who lives 100 miles away along a straight highway. the first 60 miles of the trip are driven at 55 mi/h but then you get stuck in a standstill traffic jam for 20 minutes. in order to make up time, you then proceed at 75 mi/h for the rest of the trip. what is the magnitude of your average velocity for the whole trip?

Ahydroelectric plant takes energy from water and turns it into electrical energy. what are the transformations of energy in the water molecules that are used in the process of generating electricity this way?

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

In a system, when potential energy decreases, then entropy also decreases. true false