UFM & 1st Semester Review Answers
General Physics
UFM WS 5
1b. 0.17
1c. 1.6 m/s/s
3b. 0.52 m/s/s
2b. 0.25
3c. 120 N
2c. 0.40 m/s/s
4b. 0.33
5b. -120 N
5c. 2.0 m/s/s
Newton’s 2nd Law Review Problems
1. - 76 N
2. – 7600 N, 50. m
5. 0.94 m/s/s
3. 1.0 x 102 N
4. 1118  1200 N
6. 5.0 m/s/s
UFM The Skydiver
Fg depends on mass and g
Ff depends on surface area, speed and shape of object
No – grav. field strength and mass are constant
Yes, friction depends on speed
Pt. 1
Ff = 320 N
Fg = 780N
a = -6.0 m/s/s
Fnet = - 480 N
Pt. 2
Ff = 780 N
Fg = 780 N
a = 0
Fnet = 0
Pt. 3
Ff = 1900 N
Fg = 780 N
a = 14 m/s/s
Fnet = 1120 N
Pt. 4
Ff = 780 N
Fg = 780 N
a = 0
Fnet = 0
Analysis
1. Not at all
2. The camera person continues to fall at a larger velocity that the skydiver.
3. See me
4. Part 2 velocity is greater that part 4.
5. No, Large Larry hits with greater velocity since his net force is larger (same friction force as Slim Sally
but a larger Fg for Large Larry.)