A student discovers a comet heading toward the Sun. The student records the initial distance from the Sun as 'd' while recording the initial mass of the comet as 'm' which resulted in a gravitational force of 'F'. Further observation of the comet shows that as it reaches a positon d/2, the mass of the comet has been reduced to 1/3 of its original mass. Which expression best represents the value of the gravitational force at d/2? A. F/3
B. 2F/3
C. 4F/3
D. 9F/2

The experiments with static charges were done by:

The energy equivalent of the rest mass of an electron is

An alpha particle with kinetic energy 12.5 mev makes a collision with lead nucleus, but it is not "aimed" at the center of the lead nucleus, and has an initial nonzero angular momentum (with respect to the stationary lead nucleus) of magnitude l = p0 b, where p0 is the magnitude of the initial momentum of the alpha particle and b=1.40×10−12 m. (assume that the lead nucleus remains stationary and that it may be treated as a point charge. the atomic number of lead is 82. the alpha particle is a helium nucleus, with atomic number 2.) what is the distance of closest approach?