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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):.
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Physics 1A, Section 7 October 8, 2007
A modern look athistorical laws of falling bodies • Oresme (14th century): v t s t2 (both correct)
A modern look athistorical laws of falling bodies • Galileo (17th century):
A modern look athistorical laws of falling bodies • Galileo (17th century):
A modern look athistorical laws of falling bodies • Galileo (17th century): s t2 (correct)
A modern look athistorical laws of falling bodies • da Vinci (15th century):
A modern look athistorical laws of falling bodies • da Vinci (15th century):
A modern look athistorical laws of falling bodies • da Vinci (15th century): s (t)(t + 1)/2 = t2/2 + t/2
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)
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!
OM, Problem 2-72 • Answer: acceleration = 0.48 m/s2 time = 13.8 s
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.
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.