Select the correct answer. julie is cycling at a speed of 3.4 meters/second. if the combined mass of the bicycle and julie is 30 kilograms, what is the kinetic energy? 1.7 × 102 joules 1.5 × 102 joules 2.0 × 102 joules 2.2 × 102 joules

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.

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

If an electric circuit is not grounded it is best to reach out and touch it to provide the ground a.true or b.false