12. The answer is; the satellite cools off by radiation
In the vacuum of space, there is no medium for convectional heat transfer. Only electromagnetic radiation transfer energy through space. The satellite will, therefore, lose heat through infra-red radiation, not convection.
13. The answer is; heat will transfer to her feet by conduction
When the beachgoer wears her sandals, he makes contact with the sandals and his foot and sandal becomes one thermodynamic system. The heat transfer by conduction, as it passes through the skin, seeks thermal equilibrium.
15. The answer is; elastic potential to kinetic
The more the string of the bow is pulled, the higher the elastic potential energy it gains. This is because the string is stretched and has the capacity to restore normal size when released. When the string is released and begins to rapidly restore, it transfers this energy to the arrow, pushing the arrow forward.
16. The answer is; Reduced friction means increased efficiency.
By lubricating the moving components of the engine, friction is reduced. Friction causes a loss of energy as the energy is lost through heat as the components rub against one another. Reduction of friction, therefore, reduces this loss and more energy is channeled towards the drive shaft.
17. The answer is; It increases friction by air resistance.
A parachute is designed to increase drag exceptionally hence reduce the speed of a moving object drastically. Drag is induced by frictional resistance. When the parachute deploys, air is impeded from passing smoothly over the parachute hence enormous air resistance is developed causing the space shuttle to reduce speed.
