Which statement accurately describes what happens when ice melts in terms of energy? (i think d or a) a. the ice releases energy which causes the water molecules to have less kinetic and potential energy, changing their configuration from solid to liquid. b. the ice releases energy which causes chemical bonds to break, changing the ice to water. c. the ice absorbs energy which causes chemical bonds to break, changing ice to water. d. the ice absorbs energy which causes the water molecules to have more kinetic and potential energy, changing their configuration from a solid to a liquid.

The percent efficiency of a machine can never be 100% (or greater), because in the real world some energy is always converted into a. heat b. work c. input force d. output force

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 710 n/m. it is initially at rest on an inclined plane that is at an angle of θ = 23° with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is μk = 0.19. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. a) what is the block's initial mechanical energy? b) if the spring pushes the block up the incline, what distance, l, in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.

Which simple machine is not part of this compound machine? a. lever b. pulley c. inclined plane d. wheel and axle