physics 1a, section 7
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Physics 1A, Section 7. October 8, 2007. A modern look at historical laws of falling bodies. Oresme (14 th century): v t s t 2 (both correct). A modern look at historical laws of falling bodies. Galileo (17 th century):. - PowerPoint PPT PresentationTRANSCRIPT
Physics 1A, Section 7
October 8, 2007
• Oresme (14th century): v t
s t2
(both correct)
A modern look athistorical laws of falling bodies
A modern look athistorical laws of falling bodies• Galileo (17th century):
time 1 2 3 4 5 …
s 1 3 5 7 9 …
• Galileo (17th century):
time 1 2 3 4 5 …
s 1 3 5 7 9 …
s 1 4 9 16 25 …
A modern look athistorical laws of falling bodies
• Galileo (17th century):
s t2 (correct)
time 1 2 3 4 5 …
s 1 3 5 7 9 …
s 1 4 9 16 25 …
A modern look athistorical laws of falling bodies
• da Vinci (15th century):
time 1 2 3 4 5 …
s 1 2 3 4 5 …
A modern look athistorical laws of falling bodies
• da Vinci (15th century):
time 1 2 3 4 5 …
s 1 2 3 4 5 …
s 1 3 6 10 15 …
A modern look athistorical laws of falling bodies
• da Vinci (15th century):
s (t)(t + 1)/2 = t2/2 + t/2
time 1 2 3 4 5 …
s 1 2 3 4 5 …
s 1 3 6 10 15 …
A modern look athistorical laws of falling bodies
• da Vinci (15th century):
s (t)(t + 1)/2 = t2/2 + t/2
v = ds/dt t + 1/2 (moving at the start)
time 1 2 3 4 5 …
s 1 2 3 4 5 …
s 1 3 6 10 15 …
A modern look athistorical laws of falling bodies
• Albert of Saxony (14th century): v s
A modern look athistorical laws of falling bodies
• Albert of Saxony (14th century): v s
ds/dt = s (ignored proportionality constant)
A modern look athistorical laws of falling bodies
• Albert of Saxony (14th century): v s
ds/dt = s (ignored proportionality constant)
s = et (ignored another proportionality constant)
A modern look athistorical laws of falling bodies
• Albert of Saxony (14th century): v s
ds/dt = s (ignored proportionality constant)
s = et (ignored another proportionality constant)
v = et
A modern look athistorical laws of falling bodies
• Albert of Saxony (14th century): v s
ds/dt = s (ignored proportionality constant)
s = et (ignored another proportionality constant)
v = et
Takes an infinite time to start from infinitesimal velocity!
A modern look athistorical laws of falling bodies
OM Chapter 1
OM Chapter 1, part 2
OM Chapter 2
OM, Problem 2-72
OM, Problem 2-72
• Answer: acceleration = 0.48 m/s2
time = 13.8 s
Quiz Problem 35
Quiz Problem 35
• Answer:a) a(t) = jt + a0
v(t) = jt2/2 + a0t + v0
x(t) = jt3/6 + a0t2/2 + v0t + x0
b)
c) A was ahead at t = 0.5 s.
d) J will win.0 0.5 1 1.5
time (s)
x
Car A
Car J
OM, Problem 2-99
OM, Problem 2-99
• Answer: a) n sqrt(2h/g)
b) 3h/4 above the ground
c) 2h/3 above the ground
(in the back of the book)
Thursday, October 11:
• Quiz Problem 27
• TMU, Chapter 5, problem 40
• OM Chapter 3, problem 62
• OM Chapter 3, problem 63
• Optional to work on these in advance.