A ship is cruising slowly through a channel with steep canyon walls on each side. The captain blows his foghorn and an echo from one wall is heard 4.2 s after the horn was sounded. The echo from the other wall is heard 6.5 s after the first echo. How wide is the channel? Assume the speed of sound in air is 343 m/s.

If an astronaut takes an object to the moon the following is true (choose only one). a the mass will change but the weight will be the same. b both the mass and the weight of the object will be the same. c the weight will change but the mass will be the same. d both the mass and the weight of the object will change.

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.

Convection occurs when thermal energy is transferred by the movement of