Two ideal heat engines, A and B, operate on the difference of temperatures of hot and cold reservoirs 200 K. But engine A has temperature of cold reservoir 100K, and engine B has temperatures of hot reservoir 400K. Which of these two engines has greater theoretical efficiency

Bone-strengthening physical activity done increases bone-mineral content and bone density in youth.

Scout feels ill one day before school. her mother puts a thermometer in her mouth and the temperature begins to climb to 100°f. what is happening between the cooler thermometer and scout's body? a) scout's body is applying a force to the particles in the thermometer. b) kinetic energy is being transferred from her mouth to the thermometer. c) potential energy is being lost by the thermometer and gained by scout's body. d) the potential energy stored in foods is converted to mechanical energy to raise the mercury in the thermometer.

Brutus, the dog, is pulling a bone to the left with a force of 20 n. lassie, another dog, is pulling a bone to the right with a force of 18n. what is the net force? a. b. c.