1. a sonar pulse is sent to the ocean bottom which is 25◦ celsius. it takes 4.2 seconds for the wave echo to return to the ship. how deep is the ocean bottom? medium m/s air 0○c 331 air 20○c 343 helium 0○c 972 water 25○c 1,493 seawater 25○c 1,533 copper 25○c 3,560 iron 25○c 5,130

Select all the correct answers. which changes will increase the rate of reaction during combustion? decreasing the area of contact between the reactants adding more oxygen to the reaction removing heat from the reaction changing the reactants from solid form to powdered form lowering the exposure of the reactants to air

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.

Diverging mirrors and lenses always produce images