6. According to the second law of thermodynamics. A. heat energy cannot be completely converted to work
B. work cannot be completely converted to heat energy
C. for all cyclic processes we have dQ/T < 0
D. the reason all heal engine efficiencies are less than 100% is friction, which is unavoidable

Find the momentum for a 2.6-kg brick parachuting straight downward at a constant speed of 8.4 m/s .

Which statements about tornadoes are true? check all that apply. (a) about 12,000 tornadoes hit the united states every year. (b) a tornado looks like a funnel. (c) tornadoes are deadly atmospheric storms that cause millions in damages each year. (d) tornadoes can reach wind speeds of more than 300 miles per hour. (e) kansas is the state with the most tornadoes. (f) you will always notice a funnel before a tornado strikes.

Sawyer is studying diffraction. he draws a diagram of a plane wave to show how light waves travel. which best describes sawyer’s error? the wave fronts should be perpendicular to the direction in which the waves move. the arrow showing the direction of movement of the waves should be pointing to the left. the arrow showing the direction of movement of the waves should be pointing downward. the wave fronts should be both parallel and perpendicular to the direction in which the waves move.