Answers to Quiz 1
Question 1
(Question 2 will figure out in class)
Statistics of Quiz 1
30
Number of students
25
20
15
10
5
0
1
2
3
4
5
6
Score
7
8
9
10
Statistics of Quiz 1
6
Average Score
5
4
3
2
1
0
! HW1
HW1 !
HW2
HW1 &
HW2 !
HW3
HW1 &
HW2 &
HW3
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.
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.
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.
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.
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.
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.