1. Answers to Quiz 1 Question 1 (Question 2 will figure out in class)

2. Statistics of Quiz 1

4. An object moves in the xy plane. The following plot shows the object’s path as a function of time. Assume the object follows the path from t=0s to t=10s never going backwards, but the speed may change during its path. From t=0s to t=5s the path follows a perfect circle, and from t=6s to t=10s a straight line. Decide whether each of the following statements is true: Average speed between t=1s and t=2s is larger than average speed between t=8s and t=9s.

5. An object moves in the xy plane. The following plot shows the object’s path as a function of time. Assume the object follows the path from t=0s to t=10s never going backwards, but the speed may change during its path. From t=0s to t=5s the path follows a perfect circle, and from t=6s to t=10s a straight line. Decide whether each of the following statements is true: If the speed at t=1s is the same at t=3s, then the average velocity between those times lies in the x direction.

6. An object moves in the xy plane. The following plot shows the object’s path as a function of time. Assume the object follows the path from t=0s to t=10s never going backwards, but the speed may change during its path. From t=0s to t=5s the path follows a perfect circle, and from t=6s to t=10s a straight line. Decide whether each of the following statements is true: The average velocity between t=6s and t=7s equals the average velocity between t=7s and t=8s.

7. An object moves in the xy plane. The following plot shows the object’s path as a function of time. Assume the object follows the path from t=0s to t=10s never going backwards, but the speed may change during its path. From t=0s to t=5s the path follows a perfect circle, and from t=6s to t=10s a straight line. Decide whether each of the following statements is true: At t=2s the instantaneous acceleration lies on the X direction.

8. An object moves in the xy plane. The following plot shows the object’s path as a function of time. Assume the object follows the path from t=0s to t=10s never going backwards, but the speed may change during its path. From t=0s to t=5s the path follows a perfect circle, and from t=6s to t=10s a straight line. Decide whether each of the following statements is true: If the speed is constant between t=0s and t=5s, then the instantaneous acceleration at t=4s points in the direction of x.

9. An object moves in the xy plane. The following plot shows the object’s path as a function of time. Assume the object follows the path from t=0s to t=10s never going backwards, but the speed may change during its path. From t=0s to t=5s the path follows a perfect circle, and from t=6s to t=10s a straight line. Decide whether each of the following statements is true: If the speed is constant between t=0s and t=5s, then the instantaneous velocity at t=4s points in the direction of X.