CORRECT ANSWERS
Question:
1. If two speedsters have the same speed, must they have the same velocity?
Answer:
The skaters may have the same speed, but they skate in different directions, then they have different
velocities.
Question:
2. If the average velocity of a runner is zero, does that mean she is stationary?
Answer:
No, the runner may run to the right and then turn around and return to the starting point. Her displacement
will be zero and therefore her average velocity will be zero too.
Question:
3. Imagine that a book travels around the perimeter of a table of length 3 m and width 2 m and ends up in
its original position. What is its distance of travel and its displacement?
Answer:
The distance of travel is 10m (add 3,3,2,2) and displacement is 0.
Question:
4. You throw a ball straight up. Once it reaches its highest point, it briefly stops, what is its acceleration at
that point?
Answer:
even at the top, the ball undergoes a change in velocity and has acceleration due to gravity or 9.8m/s2.
Question:
5. If a car is moving east, can its acceleration be west?
Answer:
Yes, it can be slowing down.
Question:
6. A motorbike racer in a turn maintains his speed but widens the radium of his turn. What happens to
acceleration?
Answer:
Acceleration decreases.
Question:
7. You travel for two hours but your average velocity is zero. How can that happen?
Answer:
If you return to the starting point, then your displacement is zero, therefore average velocity is zero.