In the Milky Way, the most abundant gas in emission nebulae is ____.
A. Helium
B. Hydrogen
C. Neon
D. Krypton
Ans: B. Hydrogen
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Rupel pushes a box 7.00 m by applying a 25.0-N horizontal force. What work does she do?
a. 3.57 J b. 0.280 J c. 175 J d. –175.0 J e. 25.0 J
A real (non-Carnot) heat engine, operating between heat reservoirs at temperatures of and performs 4.3 kJ of net work and rejects of heat in a single cycle. The thermal efficiency of this heat engine is closest to
A) 0.35. B) 0.31. C) 0.28. D) 0.38. E) 0.42.
A 4.00 kg object is moving at 5.00 m/s NORTH. It strikes a 6.00 kg object that is moving EAST at 2.00 m/s. The objects have a completely inelastic (stick together) collision. The velocity of the 6.00 kg object after the collision is
A. 2.33 m/s at an angle of 35.0 degrees NORTH of EAST. B. 2.33 m/s at an angle of 59.0 degrees NORTH of EAST. C. 2.00 m/s at an angle of 59.0 degrees NORTH of EAST. D. 2.00 m/s at an angle of 45.0 degrees NORTH of EAST. E. 2.33 m/s at an angle of 45.0 degrees NORTH of EAST.
The magnitude of the acceleration of an object moving in a circle at constant speed is
a. variable. b. directly proportional to the speed squared. c. directly proportional to the speed. d. directly proportional to the radius of the circle squared.