CT4-1. A bullet is fired horizontally from a rifle on the Moon (where there is no air). The initial speed of the bullet when it leaves the gun barrel is vo. Assume that the ground is perfectly level (and endless). Which of the following three statements is false:Pink: During its entire flight, the minimum speed of the bullet is vo.Yellow: The acceleration of the bullet is constant during its flight.Blue: The time it takes for the bullet to hit the ground increases as vo is increased.Green: All of the above statements are true!Answer: Blue: the time it takes for the bullet to hit the ground is independent of v0. The bullet hits the ground in the same time it would if it just dropped straight down from the end of the barrel.Regarding the pink answer, the minimum speed of the bullet is vo, the speed it has when itfirst leaves the gun. The total speed is 22o2y2xgtvvvv , which grows with time t.CT3-2. Two projectiles are fired from a cannon. For projectile A, the cannon is tilted upward at an angle twice that of projectile B. (As usual, neglect air resistance.)Which projectile was in the air longer?Blue: A Yellow: B Green: A and B were in the air the same length of time.Pink: Not enough information to answer the question.Answer: A is in the air longer. The y-motion is independent of the x-motion. So the times in the air are the same as if the x-motions were not present.ABA B A
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