Why is there a 4-minute difference between the solar day and the sidereal day?
because the Earth's rotation is variable due to the pull of the Moon.
because the Earth's axis is tilted by about 23 degrees.
because the Earth is going around the Sun in the course of a year.
because the stars slowly change their orientations in the galaxy.
because the Earth is going around the Sun in the course of a year.
You might also like to view...
Matter Waves: Electrons emerge from an electron gun with a speed of 2.0 × 106 m/s and then pass through a double-slit apparatus. Interference fringes with spacing of 2.7 mm are detected on a screen far from the double slit. What would the fringe spacing be if the electrons were replaced by neutrons with the same speed? (h = 6.626 × 10-34 J ? s, melectron = 9.11 × 10-31 kg, mneutron = 1.675 × 10-27 kg)
A. 1.5 ?m B. 4.9 m C. 0.93 nm D. 1.2 km
Buoyancy: A cylinder, semicircular in cross-section, is 10 m long and 5.0 m in radius. It is completely submerged, with its flat bottom side horizontal and 8.0 m below the water surface, as shown in the figure. What is the magnitude of the net force on the curved upper surface of the half-cylinder? Neglect atmospheric pressure.
A. 2.0 × 106 N B. 2.5 × 106 N C. 3.0 × 106 N D. 3.5 × 106 N E. 4.0 × 106 N
Which of the following depends on the observer's frame of reference?
A) the mass of the proton B) the length of a meter stick C) the half-life of a muon D) all of the other answer choices
A primary rainbow is brighter than a secondary rainbow because
A) sunlight reaching it is more intense. B) there is one less reflection inside the water drops. C) larger drops produce primary rainbows. D) the secondary bow is a dim reflection of the primary rainbow. E) none of the above