What do we mean by the event horizon of a black hole?
A) It is the very center of the black hole.
B) It is the place where X-rays are emitted from black holes.
C) It is the point beyond which neither light nor anything else can escape.
D) It is the distance from the black hole at which stable orbits are possible.
C
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An 3000-kg car traveling at 70 m/s takes 8 m to stop under full braking. The same car under similar road conditions, traveling at 140 m/s, takes ______________ to stop under full braking.
a. 16 m b. 3 m c. 8 m d. 32 m e. 18 m
Which galaxy, as observed, has aged the most since it was born?
A) a very distant galaxy B) a nearby galaxy C) The distance of a galaxy doesn't matter.
A horizontal 52-N force is needed to slide a 50kg box across a flat surface at a constant velocity of 3.5 m/s. What is the coefficient of kinetic friction between the box and the floor?
A) 0.11 B) 0.13 C) 0.10 D) 0.09
A 120-kg refrigerator, 2.00 m tall and 85.0 cm wide, has its center of mass at its geometrical center. You are attempting to slide it along the floor by pushing horizontally on the side of the refrigerator
The coefficient of static friction between the floor and the refrigerator is 0.300. Depending on where you push, the refrigerator may start to tip over before it starts to slide along the floor. What is the highest distance above the floor that you can push the refrigerator so that it won't tip before it begins to slide? A) 0.710 m B) 1.00 m C) 1.21 m D) 1.42 m E) 1.63 m