Lesson 6 - Answers to Suggested Problems
After you have had a chance to try the suggested
end-of-chapter conceptual questions, problems and exercises,
you can check your answers against mine below. (Please alert
Jason Harlow jharlow@physics.utoronto.ca if you notice any
errors in the answers.)
Conceptual
Questions
20. 9.80 m/s2, down. 9.80 m/s2,
down. 9.80 m/s2, down.
23. It would be slower, since energy was lost pushing away
the air. It would not go as high, since it encounters
resistance on the way up.
25. 6 times higher
26. (a) the slope at each point is the velocity (b) ta
(c) td (d) te
28. (a) Average acceleration is change in velocity divided
by elapsed time: a = (v2 - v1)/(t2
- t1). The acceleration is increasing from t1
to t2.
Problems and Exercises
43. 4.95 m/s
45. (a) Knowns: v0 = 13.0 m/s, a = -9.80 m/s2,
vf = 0 (b) 8.62 m This seems pretty high but I
looked it up on the internet and it said that dolphins can
be trained to jump between 15 and 30 feet. This is 28
feet so yes it's reasonable. (c) 2.65 s
49. 1.91 s
52. (a) 4.9 m (b) 38.3 m/s (c) 33.4 m
55. (a) 19.6 m (b) 18.5 m
58. (a) 5.42 m/s, down (b) 4.64 m/s, up (c) 2880 m/s2
(d) 5.11 mm
65. (a) 6 m/s (b) 12 m/s (c) 3 m/s2 (d) 10.3 s