Units Vectors and Motion
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
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