According to Kepler results in mid-2013, what fraction of stars host an Earth-size planet?
A) about 20% B) about 100% C) about 15% D) about 70%
C
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By Newton's Third law, Earth's pull on the Moon is equal to the Moon's pull on Earth.
Answer the following statement true (T) or false (F)
A proton moving at a speed of 4.2 × 10^6 m/s cuts across the lines of a magnetic field at an angle of 78°. The strength of the field is 0.91 × 10^?4 T. What is the magnitude of the force acting on the proton? (qp = 1.6 × 10^?19 C)
a. 1.3E–17 N b. 3.1E–17 N c. 6.0E–17 N d. 7.2E–9 N e. 9.6E–36 N
A stunt pilot weighing 0.70 kN performs a vertical circular dive of radius 0.80 km. At the bottom of the dive, the pilot has a speed of 0.20 km/s which at that instant is not changing. What force does the plane exert on the pilot?
A. 3.6 kN up B. 4.3 kN up C. 2.9 kN down D. 2.9 kN up E. 5.8 kN down
All planets rotate in the counterclockwise direction as seen from the north
a. True b. False Indicate whether the statement is true or false