Super physics teacher choice Green

Super physics teacher choice Green Meria Nakamura

Question: A high powered rifle can shoot a bullet at a speed of 1500 mi/hr. On the moon, with almost no atmosphere and an acceleration due to gravity of 1.6 m/s2, a bullet shot straight into the air would take how long to return to the moon’s surface? On Earth, a standard .30 caliber bullet fired from a rifle pointed straight up would rise to an altitude of 9,000 feet (2,743.2 m) in 18 second, and then would return to Earth in another 31 seconds. How much influence does the atmosphere have on a bullet fired from the surface of the Earth?

The moon: How long would take to return? Initial velocity: 1,500 x 1.6 = 2,400 0 = 2,400 - 1.6t 1,500 = t Time of descent will also be the same time of flight: 2 x 1,500 = 3000s

The earth: Influence of atmosphere V=u-axt 0 = u - a x 18 U = 18a V2 = u2 - 2 x a x 2643.2 0 = (18a)2 - 2 x a x 2743.2 A = 16.93 DOWNWARD RETURN S = ut + ½ a2 x t2 2643.2 = 0 + .5 x a2 x 313 A2 = 5.7 m/s2