A sailboat of mass m is moving with a momentum p. Which of the following represents its kinetic energy?
A) p2/2m
B) mp
C) mp/2
D) 1/2 mp2
E) mp/3
Question 2If you run a complete loop around an outdoor track (400 m) in 100 s, your average velocity is
A) 0.25 m/s.
B) 4.0 m/s.
C) 40,000 m/s.
D) zero.
E) 4.00 km/s.
Question 3Dust and smoke blown up into the Earth's atmosphere from the massive impact of an asteroid 65 million years ago
A) removed most of the oxygen in the Earth's atmosphere by oxidation
B) rapidly escaped into space, having very little effect on the Earth's climate
C) blocked sunlight, causing global temperatures to fall on the Earth and subsequently shutting down photosynthesis for up to a year
D) trapped heat in the Earth's atmosphere, causing global temperatures to rise
Question 4The results of statistical studies of the exoplanet systems discovered to date suggest that
A) planets are common
B) small planets outnumber large plates by a significant margin
C) Earth-size planets are very common
D) all of these are true
Question 5Some automobiles have air bags installed on their dashboards as a safety measure. The impact of a collision causes the bag to inflate, and it then cushions a passenger's head when he is thrown forward in the car.
Suppose that such a bag could lengthen the collision time between one's head and the dashboard by a factor of 10. What effect would this have on the force exerted on the head? A) The force would be reduced by a factor of about 3.
B) The force would be reduced by a factor of about 1000.
C) The force would be reduced by a factor of about 10.
D) The force would not be reduced, but the energy transferred to the head would be, thereby minimizing the damage done.
E) The force would be reduced by a factor of about 100.
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