# PHYSICS 151

##### University of Hawaii, Manoa Dept. of Physics & Astronomy

Instructor: Michael Nassir
Office: Watanabe Hall, Rm. 426, (808) 956-2922
E-mail: nassir @ hawaii.edu

## ANSWERS to MIDTERM #1 from SPRING 2004

Part A

1. C
2a. B
2b. 6.00 x 10^-3 kg
3. E
4. D
5. B
6. D
7a. B
7b. A
8a. B
8b. B and D
9a. C
9b. E

Part B

1a. v_0x = 24.7 m/s, v_0y = 24.7 m/s
(24.75 m/s can be used in subsequent parts, to prevent roundoff error)
1b. 31.2 m
1c. When x = 100 m, t = 4.04 s. At that time, y = 19.9 m. The fence is only 10.0 m tall, so the ball DOES clear the fence.
OR: When y = 10.0 m, t = 0.443 s (on ascent) and t = 4.60 s (on descent). At t = 4.60 s, the ball has reached x = 114 m. Since the fence is only 100 m away, the ball DOES clear the fence.

2a. +22.5 m/s
2b. Straight downward-sloping line from (0 s, +22.5 m/s) to (15 s, -15 m/s);
straight horizontal line from there to (25 s, -15 m/s);
upward-sloping line from there to (35 s, 0 m/s);
straight horizontal line from there to (40 s, 0 m/s).