# Physics 1401

## Online Quiz 10

### Chapters 9 & 10 in Conceptual Physics 12th edition

Question 1. A projectile is fired from the top of a cliff as shown below. Which of the paths 1-5 would the projectile most likely follow?
(a) 1     (b) 2     (c) 3     (d) 4     (e) 5

Question 2. A bowling ball accidentally falls out of the cargo bay of an airliner as it flies along in a horizontal direction. As observed by a person standing on the ground and viewing the plane as in the figure below, which of the paths 1-5 would the bowling ball most closely follow as it falls to the ground.
(a) 1     (b) 2     (c) 3     (d) 4     (e) 5

Question 3. A boy on a tower throws a ball so that it leaves his hand horizontally and at a height above the ground of 20 m. How many seconds does it take for the ball to hit the ground?
(a) 1     (b) 2     (c) 3     (d) 4     (e) 5

Question 4. If the ball in the previous question lands on level ground at a distance of 20 m from the tower, how fast (in m/s) did the ball leave his hand?
(a) 5     (b) 10     (c) 15     (d) 20     (e) 25

Question 5. A cannon fires a projectile at an angle of 45o. The projectile will follow a curved path until it impacts the ground. Neglecting air resistance, how far below a straight-line path will the projectile fall in 3 seconds?
(a) 1 m     (b) 5 m     (c) 20 m     (d) 30 m     (e) 45 m

Question 6. Who was the best naked-eye (pre-telescope) astronomer whose observations were precise enough to determine the actual motion of the planets?
(a) Copernicus
(b) Brahe
(c) Newton
(d) Kepler
(e) Blowthor, TWG

Question 7. Who used the data from these observations to show that the planets move in elliptical orbits about the sun?
(a) Copernicus
(b) Brahe
(c) Newton
(d) Kepler
(e) Blowthor, TWG

Question 8. Who developed a theory of gravity that explained the elliptical motion of the planets?
(a) Copernicus
(b) Brahe
(c) Newton
(d) Kepler
(e) Blowthor, TWG

Question 9. If the universal gravitational constant G = 6.7×10-11N m²/kg², the mass of the earth me = 6×1024 kg, and the radius of the earth Re = 6.4×106 m, then the value (in m/s²) of the quantity [G me/Re2] is approximately
(a) 0     (b) 5     (c) 10     (d) 15     (e) 25

Question 10. In the previous question you computed the value of ag at the earth's surface as approximately 10 m/s². The value of the acceleration of gravity ag (in m/s²) at a distance from the earth's center of two times the radius of the earth is
(a) 0     (b) 0.625     (c) 2.5     (d) 5.0     (e) 10.0

Question 11. How far (in m) will a spacecraft fall out of its straight-line trajectory in 1 s if it is in orbit at a distance from the earth's center of two times the radius of the earth?
(a) 0     (b) 0.313     (c) 1.25     (d) 2.5     (e) 5.0

Question 12. If the acceleration due to the earth's gravity is 0.1 inch/s² at a distance 60 Re from the center of the earth, how far (in inches) will the moon fall out of its straight-line trajectory in 1 s?
(a) 0     (b) 0.05     (c) 0.10     (d) 6.0     (e) 9.0

Question 13. Who proved his theory of gravity by showing that the moon drops 1/20th of an inch below its straight-line path every second?
(a) Copernicus
(b) Brahe
(c) Newton
(d) Kepler
(e) Blowthor, TWG

Question 14. If the force of gravity between two objects a distance d apart is 8 N, then when the separation distance between the objects is increased to 2d the force of gravity (in N) becomes
(a) 0     (b) 2     (c) 4     (d) 8     (e) 16

Question 15. On earth, the tides are caused primarily by
(a) the sun
(b) the moon
(c) El Niño
(d) the tenth planet
(e) Baywatch

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