Wind energy spins the blades on this wind turbine. the mechanical energy of the moving blades is used to generate electricity. but wind turbines are not suited to all areas of the country, because in some places there is not enough wind.

why is an external energy source, in this case wind, needed to keep the blades spinning?
a) wind energy is required for energy transformations.
b) without an external energy source, friction stops the blades.
c) wind energy is required to convert potential energy to kinetic energy.
eliminate
d) the internal energy will overcome the external energy and the blades will stop spinning.

When temperature of a substance increases, of its particles increase resulting in more between particles. real world applications of thermal expansion absolute zero (-273 degrees c) is the lowest possible temperature on the kelvin scale. it is a measure of where a substance has no kinetic energy. heat is a process of the . energy flows spontaneously from a object to a until equilibrium is reached. heat is measured in heat is transferred throughis a method of heat transfer that occurs between particles of matter that are in direct contact with each other. are poor conductors that impede / reduce the rate of heat transfer. is a method of heat transfer that occurs in fluids (non-solids) by means of currents. real world application of convectiona method of heat transfer through electromagnetic waves. when energy moves from one object to another inside a closed system, no energy is or in the system in the transaction. systems will spontaneously move to a state of organized energy or high disorder over time called

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?

1kg of water needs to recieve 4200j of energy to go from 90 degrees to 91 degrees. what is the specific heat capacity of water? what are the units?