HW26: Practice Problems for Final Exam

The answers to the unanswered problems are as follows:
1) B,
2) 0.667 s,
3) 7 m,
4) b
7) d
8) b, d, e,f
9c) 60 deg,
11) Objects settle when not moving so there is more resistance to overcome to start an object movingand thus greater coefficient of static friction
12a) arrow up same size as arrow down,
12b) arrow up same size as arrow down,
12c) arrow up same size as arrow down and arrow to right bigger than friction arrow to left,
12d) 895N up arrow, 861N right arrow, 651N down arrow, 458 N left arrow,
13a) B, 13b) C
15a) 5 kg
17a) x 2, 17b) x 1/4, 17c) x 4, 17d) x 16 ,
19) the ping pong ball would need greater than 2037 times the speed of the bowling ball to have greater momentum,
20c) 4.08 s
21b) 20.0 m Can't have greater PE than total ME
23) since change in momentum same no matter how you stop, the airbag increasing the time to stop reduces the Force because F=(change momentum)/(time to stop),
26b) 7.35 m,
26c) 3.24 x 10^5 N and the weight (0.29 N) is insignificant,
29) 2.35 m/s2
31) 3.94 s
32) -38 J
33) 15.3 cm at 58.4 deg North of East
34) Your inertia holds you in place as the jet accelerates forward.  There is no force pushing you back.  The only forces are gravity (down), seat (normal force, up), and when it reaches you, the seat back pushing you forward.
35a) 18700 N,
35b) 16660N,
35c) 15640 N
36a) 1421 N,
36b) 539 N,
36c) 0 N
37) D
38) D
39) A
40a) horizontal line greater than 0,
40b) line starting at zero and increasing with positive slope,
40c) horizontal line equal to 0
40d) horizontal line less than 0