1. An astronaut’s weight on the moon is 150 N. (Take the moon’s radius to be 1600 km.) The astronaut’s weight when he is 3200 km above the moon’s surface is
a) zero; b) 50 N; c) 37.5 N;
d) 16.7 N.
2. In the law of universal gravitation, the force between two objects, A and B, is
a) inversely proportional to the mass of A,
b) inversely proportional to the square of the mass of A,
c) directly proportional to the mass of A,
d) directly proportional to the square of the mass of A.
3. The Cavendish experiment was the first measurement of the constant, G, in the law of universal gravitation. Once G was determined, it was possible to determine
a) the acceleration, g, of objects falling near the earth
b) the mass of the earth
c) the mass of the moon
d) the acceleration of the moon in its orbit.
4. We calculated the acceleration of the moon in its orbit around the earth to be, amoon = 0.00273 m/s2. The distance from the earth to the moon is about 385,000 km. If a second moon were found to be in orbit around the earth at a distance of 600,000 km, what would its acceleration be?
a) 0.00112 m/s2. b) 0.00175 m/s2. c) 0.00273 m/s2. d) 0.00426 m/s2.
5. Stars range in mass from about one-tenth of the sun’s mass up to
a) about twice the sun’s mass
b) about 10 times the sun’s mass
c) 1000 times the sun’s mass
d) no known upper limit
6. By observing the orbit of Titan, one of the large satellites of Saturn, we can deduce the mass of
a) Titan;
b) Rhea, another large satellite of Saturn;
c) Saturn;
d) the sun.
7. The recent discovery that Pluto has a satellite led to a new picture of Pluto as an “icy” planet, rather than a “rocky” one. This is because its
a) orbit is now known to be more elliptical than previously thought,
b) temperature is reduced by the presence of the satellite,
c) mass is now known to be more than previously thought,
d) mass is now known to be less than previously thought.
8. If the moon and the earth had about the same mass,
a) they would both orbit about a point approximately half-way between them,
b) their orbits would have to be very elliptical,
c) the earth’s gravitational force would not be able to keep the moon in orbit,
d) the moon would fall into the earth.
9. An astronaut in a spaceship orbiting the earth feels “weightless” because she
a) is going in the same orbit as the spaceship;
b) is very far from the earth’s surface;
c) moves very rapidly in the spaceship;
d) is in an environment without air.
10. Halley’s comet is seen only once every 75 years because
a) its orbit is a large circle about the sun;
b) it has an elliptical orbit with the sun at the center of the ellipse;
c) it is usually overhead only during daylight hours;
d) it has an elliptical orbit with the sun near the end of the ellipse.
11. When astronomers see a wiggly path in the motion of a star, they can
a) verify the inverse-square dependence in the law of universal gravitation
b) determine the value of G, the gravitational constant
c) determine the mass of the star
d) determine the mass of the star’s invisible companion.
12. The importance of the Hubble space telescope is
a) that it allows one to eliminate the effects of turbulence in the earth’s atmosphere
b) provides a magnification of star images much greater than what was possible before
c) that it eliminates the problem which arises when we observe from the moving earth, and the earth’s orbit is not perfectly known
d) that it eliminates the absorption of light by the atmosphere, which greatly reduces the brightness of photographic images.
13. An object has a mass of 2 kg. I hold it in my hands for 15 s without moving it. The work that I do is
a) 19.6 newtons b) 30 newtons c) 2 newtons d) zero
14. An object with a mass of 2 kg is held 2 meters above the floor and then dropped. From the time it is dropped until just before it hits the floor
a) its kinetic energy increases by 19.6 joules
b) its kinetic energy increases by 39.2 joules
c) its kinetic energy decreases by 39.2 joules
d) it total energy increases by 19.6 joules
15. An object is pushed with a constant force along a table. It moves at constant velocity. In this process the work-energy theorem would say:
a) work done by the force equals increase in total mechanical energy
b) work done by the force equals increase in molecular energy
c) total mechanical energy (potential + kinetic) is increased
d) total mechanical energy is decreased
16. An object of mass = 0.2 kg is released from rest and falls for 0.5 seconds. Its kinetic energy after the fall is
a) 2.40 joules b) 0.49 joules c) 4.80 joules d) 0.050 joules
17. 2.5 liters of water is heated by 10 degrees Celsius in 2.8 minutes. How long does it take to heat 3 liters of water (with the same heat source) by 10 degrees?
a) 3.36 minutes b) 2.33 minutes c) 4.03 minutes
18. 600 ml of water at 10 degrees is mixed with 200 ml of water at 9 0 degrees. The final temperature is T. Which of the following values of T is consistent with the conservation law for heat?
a) T = 20 deg. b) T = 30 deg. c) T = 70 deg.
19. A gas is confined in a jar and its pressure (p) is measured at a series of temperatures (T) between –30 degrees and +120 degrees Celsius. A graph of pressure vs. temperature shows:
a) A straight line through the origin at T = 0, p = 0.
b) A straight line through the point T = –30, p = 0.
c) A parabola that passes through the origin.
d) A straight line through the point T = -273 and p = 0.
20. The energy of molecules of a gas is primarily in the form of
a) potential energy associated with inter-molecular forces
b) potential energy assiciated with the force of gravity
c) oscillatory motion
d) kinetic energy