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Part A
1a. 0.50 J
1b. 0.50 J
1c. A and D
1d. E
2. B
3a. F
3b. D
3c. A
4. B
5. C
6. C
7a. C
7b. F
Part B
1a. 3.5 m/s
1b. zero (F_tension is perpendicular to path at all times,
so theta = 90deg at all times. Thus, W = F*d*cos(theta) = 0.)
1c. 0.50 kg (centripetal force = tension in the cord)
2a. A (Phobos)
2b. A (Phobos)
2c. 7.66 or 7.67 hours
2d.(i.) 2.01 x 10^-6 N
2d.(ii.) 6.67 x 10^-7 N
The gravitational force of Phobos on a Martian is only 3.0 times
greater than that exerted by a second Martian standing 1.0 meter
away. The gravitational effect of several Martians standing nearby
is comparable, if not greater, than the gravitational influence
of Phobos. It is therefore invalid to think that the position
of moons in the sky has any significant gravitational effect on
Martians or their actions. (Any such astrological "influence"
would need to invoke some other magical force besides gravitation.)