According to the scientific observation that energy is conserved in a "closed system,” no machine can do work on its surrounding environment forever. this observation has been made over and over again in all sciences, and no example has been found that disproves the fact of conservation of energy. the fact that energy is always conserved in a closed system is what type of scientific statement? a law a theory an inquiry a hypothesis

A1000-kg weather rocket is launched straight up. the rocket motor provides a constant acceleration for 16-s, then the motor stops. the rocket altitude 20-s after launch is 510-m. you can ignore any effects of air resistance. a. what was the rocket’s acceleration during the first 16-s? b. what is the rocket’s speed as it passes through a cloud 5100-m above the ground?

An engineer designs a roller coaster so that a car travels horizontally for 152 ft, then climbs 137 ft at an angle of 34.0° above the horizontal. it then moves 137 ft at an angle of 48.0° below the horizontal. if we take the initial horizontal motion of the car to be along the +x-axis, what is the car's displacement? (give the magnitude of your answer, in ft, to at least four significant figures and give the direction of your answer in degrees counterclockwise from the +x-axis.)

The softest and hardest minerals are: softest hardest