How would a system which exchanges energy but does not exchange matter between the system and the surroundings be classified?

Asmall 21 kilogram canoe is floating downriver at a speed of 1 m/s. what is the canoe's kinetic energy?

The electric potential v is constant everywhere within a certain region of space. which statement below is true? the choices are: the electric field is also constant (but not zero) within the region. a charged particle placed within the region will experience an electric force. the electric field is zero everywhere within the region. the electric field varies from place to place within the region.

Amagnetic field applies forces on: a)static chargesb)moving chargesc)water flow