# Units, Vectors, and Motion

I don’t understand this Physics question and need help to study. 1. Describe a situation in which average velocity is equal to instantaneous velocity? 2. Can an object with constant acceleration reverse its direction of travel? Can it reverse its direction twice? In both cases, explain your reasoning. 3. A package falls out of an airplane that is flying in a straight line at a constant altitude and speed. If you ignore air resistance, what would be the shape of the path of the package as observed by the pilot? As observed by a person on the ground? 4. A baseball player hits a ball that soars high into the air. After the ball has left the bat, and while it is traveling upward, what is the direction of acceleration? Ignore air resistance. . 1. Orange Krypton. How many wavelengths of orange krypton-86 light would fit into the thickness of a piece of paper? 2. Fastest Man on Earth. A world’s land speed record was set by Colonel John P. Stapp when in March 1954 he rode a rocket-propelled sled that moved along a track at 1020 km/h. He and the sled were brought to a stop in 1.4 s. In terms of g, what acceleration did he experience while stopping? 3. Kicking an Extra Point.  In football, after a touchdown the team has the opportunity to earn one more point by kicking the ball over the bar between the goal posts. The bar is 3m above the ground, and the ball is kicked from ground level, 12m horizontally from the bar. If the ball is kicked at 45.0° above the horizontal, what must its initial speed be if it is just to clear the bar? 4. If a = (-2,3,1), b = (0,4,0), and c = (-1,3,3), then find (a × b) ⋅ c