Chapter 3, Continued

1. 0 Chapter 3, Continued September 14, 2005

2. 90 A canon is fired with a horizontal velocity of 10 m/s and a vertical velocity of 20 m/s. Which of the following is true about the motion? • Both the horizontal and vertical motion have constant velocity. • Both the horizontal and vertical motion have constant (nonzero) acceleration. • The vertical motion has constant velocity and the horizontal motion has constant acceleration. • The vertical motion has constant acceleration and the horizontal motion has constant velocity.

3. 90 A canon is fired with a horizontal velocity of 10 m/s and a vertical velocity of 20 m/s. The cannon ball lands 100 m away. How long did it take to land? • 10 s • 20 s • 5 s • I need more information to solve this problem.

4. 60 A hockey puck slides on the ice in a northward direction. A gust of wind accelerates the puck briefly toward the east. The puck's velocity is now toward the • Northeast • East • North • Depends on the duration and magnitude of the acceleration.

5. 1 2 3 4 90 For a cannon on Earth, the cannonball would follow path 2. Instead, if the same cannon were on the Moon, where g = 1.6 m/s2, which path would the cannonball take in the same situation? • 1 • 2 • 3 • 4

6. h 1 2 3 4) all have the same hang time 90 Which of the 3 punts has the longest hang time? • 1 • 2 • 3 • All have the same hang time

7. 90 1 2 A battleship simultaneously fires two shells at two enemy submarines. The shells are launched with the same initial velocity. If the shells follow the trajectories shown, which submarine gets hit first ? • 1 • 2 • Both at the same time

8. :90 0 You are trying to hit a friend with a water balloon. He is sitting in the window of his dorm room directly across the street. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him?? • yes, it hits • maybe -- depends on the speed of the shot • no, it misses • the shot is impossible • not really sure Assume that the shot does have enough speed to reach the dorm across the street.

9. :90 You’re on the street, trying to hit a friend with a water balloon. He sits in his dorm room window above your position. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him?? • yes, it hits • maybe – it depends on the speed • no, it misses • the shot is impossible • not really sure Assume that the shot does have enough speed to reach the dorm across the street.

10. :90 You’re on the street, trying to hit a friend with a water balloon. He sits in his dorm room window above your position and is aiming at you with HIS water balloon! You aim straight at him and shoot and he does the same in the same instant. Do the water balloons hit each other?? • yes, it hits • maybe – it depends on the speed • no, it misses • the shot is impossible • not really sure

11. 90 A cart travels horizontally across a table and at some point shoots a ball straight up from its center. Where does the ball land? • In front of the cart. • The center of the cart. • Behind the cart. v