Graded Exam #3

Question 5 Correct 6.00 points out of 6.00 Question 6 Correct 6.00 points out of 6.00 The reference frames A and A ′ describe events with unprimed coordinates ( x , y ) and primed coordinates ( x ′, y ′ ), respectively. Relative to A , A ′ moves at a constant speed v in the direction of negative y . If the origins of the two frames coincide at the instant t = 0, which of the following equations correctly relates the coordinates y and y ′ ? Select one: a. y′ = y b. y′ = y − vt c. y′ = y + vt d. y′ = yvt Recently it was discovered that a planet with mass 1 . 3 × 10 kg orbits the star 70 Virginis, which is 59 light years from the Earth. 70 Virginis has approximately the same mass as the Sun, at 1 . 9 × 10 kg. If the planet is in a nearly circular orbit of radius 7 . 1 × 10 m what is the period of the planet in terms of Earth-days? Select one: a. 58 days b. 122 days c. 1200 days d. 1480 days 28 30 10 0

Question 12 Correct 6.00 points out of 6.00 Question 13 Correct 6.00 points out of 6.00 When an asteriod that is headed directly for Earth is a distance of 8 Earth radii from Earth’s center, it has a speed of 15 km / s. What is the speed of the asteroid when it collides with the Earth? Ignore any frictional effects of the atmosphere. The mass of the Earth is 5 . 98 × 10 kg and the Earth’s radius is 6 . 37 × 10 m. Select one: a. 110,000 km / s b. 10 . 5 km / s c. 330,000 km / s d. 18 . 3 km / s When viewed from above, a particular car has an area . Each of its four tires holds a pressure, , and contacts the ground with an area of . If atmospheric pressure is , which of the following is the correct expression for the weight of the car? Select one: a. b. c. d. 24 6 0

Question 18 Correct 6.00 points out of 6.00 A small airplane and a hot air balloon are moving horizontally towards each other. Relative to the ground, the plane travels at a speed of 135 m / s and the balloon travels at a speed of 7 m / s. Suppose that someone throws a tomato out of the basket of the hot air balloon, as shown. At a particular instant, the tomato is traveling horizontally with a speed of 28 m / s relative to the balloon. According to Galilean (or classical) relativity, what is the velocity of the tomato relative to the airplane? Select one: a. 156 m / s b. 114 m / s c. 100 m / s d. 170 m / s 0

Question 23 Correct 6.00 points out of 6.00 Question 24 Correct 6.00 points out of 6.00 Which of the following statements is true for any completely enclosed ideal ±uid? Select one: a. As the pressure changes at one end, this pressure change diminishes as it reaches the walls and opposite end of the enclosure. b. A pressure change at one end produces a direction-dependent pressure change in the other end. c. An increase in pressure at one end of the enclosure causes a decrease in the pressure in the opposite end of the enclosure. d. Any change in pressure is transmitted equally to all points in the ±uid. NASA wants to launch a new satellite that will remain in a circular orbit 300 km above the surface of the Earth. Determine the orbital speed necessary for the satellite to remain in this orbit if the mass of the Earth is 5 . 97 × 10 kg and its radius is 6 . 38 × 10 meters. Select one: a. 5200 m / s b. 7720 m / s c. 36,400 m / s d. 6 × 10 m / s 24 6 7 0