Based on the law of conservation of energy, how can we reasonably improve a machine’s ability to do work? a. move the machine to a different gravitational field. b. increase the friction between its moving parts. c. reduce the friction between its moving parts. d. redefine the machine’s system boundaries.

Which energy transformation occurs in the core of a nuclear reactor? nuclear energy mechanical energy nuclear energy - thermal energy thermal energy -- nuclear energy mechanical energy - nuclear energy

Ateam of astronauts is on a mission to land on and explore a large asteroid. in addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. with what minimum initial speed vesc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? assume that the asteroid is approximately spherical, with an average density p 3.84 x108 g/m3 and volume v 2.17 x 1012 m3 recall that the universal gravitational constant is g 6.67 x 10-11 n m2/kg2

Polly is pushing a box across the floor with a force of 30 n. the force of gravity is –8 n, and the normal force is 8 n. which value could describe the force of friction if polly could not move the box?