A solid lead sphere of radius 10 m (about 66 ft across!) has a mass of about 57 million kg. If two of these spheres are floating in deep space with their centers 20 m apart, the gravitational attraction between the spheres is only 540 N (about 120 lb). How large would this gravitational force be if the distance between the centers of the two spheres were tripled?
A. 60 N
B. 180 N
C. 1620 N
D. 4860 N
Ans: A. 60 N
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Nuclear Binding Energy: When a stationary plutonium-239, 
Pu, decays into uranium-235 plus an alpha particle, the energy released in the process is 5.24 MeV. The following masses are known:
What is the mass of the 
Pu nucleus, in amu? (1 u = 931.494 MeV/c2)
A. 239.05215 u B. 239.02775 u C. 239.00189 u D. 238.99919 u E. 238.98884 u
The water flowing over Niagara Falls drops a distance of 50. m. Assuming that all the gravitational energy is converted to thermal energy, by what temperature does the water rise?
What will be an ideal response?
An athlete competing in long jump leaves the ground with a speed of 9.14 m/s at an angle of 35.0° above the horizontal. What is the length of the athlete's jump?
A) 0.876 m B) 8.01 m C) 12.0 m D) 16.8 m E) 4.01 m
A circuit consists of 2N resistors, all of resistance R, connected as shown below. A potential difference V is applied to one end, and the other end is at ground potential. The equivalent resistance of the circuit is
a.
.
b.
R.
c.
