A particular lightbulb produces 8 J of thermal energy while producing 2 J of radiant energy, and this is its entire energy output during this time. How energy-efficient is this bulb as a producer of light?
A) 400 B) 20 C) 25 D) 500 E) 80
Question 2
A 3.0-kg object and a 5.0-kg object hang vertically at the opposite ends of a rope that goes over an ideal pulley. If the objects are gently released from rest, how long does it take for the 3.0-kg objects to rise by 1.0 m?
A) 0.41 s
B) 0.74 s
C) 0.82 s
D) 1.8 s
E) 0.90 s