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?
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.
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