Match each word to the sentence where it best fits.
 The rate of change of velocity is _______
 A/An __________ equation contains at least one term in which an unknown variable is squared.
free fall   terminal velocity  
 The constant speed a falling object reaches when air friction and weight are equal is called the ______.
 A thrown ball is approximately in ________ when it leaves your hand.
 What does the graph of distance versus time look like when an object is accelerating?
 A motionsensing lab car is used to explore motion in various different situations resulting in the four velocity versus time graphs shown.
(There may be more than one correct answer for each question.)
 Which of these graphs shows an acceleration of zero?
 Which of the graphs shows constant acceleration?
 Which graph shows the smallest amount of distance traveled?
 Which of these graphs would not create a curved distance versus time graph?
 Which graph shows the greatest average acceleration?
 Which of the graphs most likely represents motion with an acceleration in the same direction as the velocity?
 The position equation, x = x_{0} + v_{0}t + ½at^{2}, has three terms. Write down the physical significance for each of the three.
 In the equation v − v_{0} = at, what does the term v − v_{0} represent?
   A student asks a friend the following question:
“How is acceleration different from velocity?”
Which of the following answers would best help the student understand acceleration? Why do you think so? Ask the question yourself to some friends and think about their answers.
 Acceleration has units of m/s^{2} while velocity has units of m/s.
 How do you describe a change in speed from 10 to 20 mph that occurs over 2 s?
 Write a sentence defining acceleration.
Next, write a sentence that is equivalent to the equation that defines acceleration.
Compare the two sentences. Is your definition of acceleration the same as the equation? Why or why not?
 The four position versus time graphs above were generated by the motion of a small car with realtime technology (photogates) that sensed the motion of its wheels.
 Which of these is showing accelerated motion?
 Which graph would create a sloped (up or down) velocity versus time graph?
 Which of the graphs has a negative velocity?
 Which of the graphs shows an object at rest?
 Which of the graphs show an object whose equation of motion could be written as
$$x=15\text{m}(3\text{m/s)}t\text{?}$$
 Write down an equation for position versus time that could fit graph D.
 In which graph does time vary as the square root of position?
 In which graph does position not vary as a function of time?
 If a bird flies at the constant velocity of 125 m/s, then what is its acceleration for the first 5 s?
 Describe what constant positive acceleration looks like on an acceleration versus time graph, a velocity versus time graph, and a distance versus time graph.
 Which of the following might be described by a positive initial velocity and a negative constant acceleration?
 The brakes are applied to a car traveling at 30 mph to reduce its speed to 20 mph.
 A car starts at rest and then begins to move backward with increasing speed.
