Here are the answers I have for the practice problems for Midterm #2 that I posted on the web: Physics and Forensics c) 0.1 m/s right d) 19.5 J Ch. 5 practice problem (i.e., problem #4 from a previous midterm #1 involving disk on rotating platform): b) F_c = f_s = m {omega}^2 r c) 0.4 N d) 0.43 Ch. 6 practice problem: b) 31.9 m c) some KE goes to friction work, PE not as great, height is smaller d) 48.5 J, 2.2 N downward Ch. 7 practice problem: 1) deflected toward black side 2) 0.01 m/s 3) poorly worded question; F = same, a is greater for car Ch. 8 practice problem: a) 9.8e-5 rad/s^2 b) 1.2e-2 rad/s c) 2.1 N d) 6.9e-5 rad e) v increases Fall 2001 Midterm #2: 1.1) F perpendicular to ds, W = 0 1.2) more work done on marble 1.3) impulse is the same, ball has larger a 2.1) v_c = 3.1e3 m/s, much larger than v, orbit is elliptical 2.2) a) 118.7 N b) 7.3 rad/s c) 3.2 rad/s 3.1) a) 57 kg m/s b) 28 m/s c) 2.75 m/s d) 756 J e) 0.11 rad/s