Unformatted text preview: all angle assumption the motion is periodic with period τ0 = 2π l/g . In this problem
we will use Mathematica to ﬁnd the period for large oscillations as well: ˙
(a) Using conservation of energy, determine φ as a function of φ, given that the pendulum starts at rest at a
starting angle of Φ0 . Now use this ODE to ﬁnd an expression for the time the pendulum takes to travel
from φ = 0 to its maximum value Φ0 . (You will have a formal integral to do that you cannot solve
analytically! That’s ok, just write down the integral, being very explicit about the limits of integration)
Because this time is a quarter of the period, write an expression for the full period, as a multiple of τ0 . (b) Use MMA to evaluate the integral and plot τ /τ0 for 0 ≤ Φ0 ≤ 3 rad. For small Φ0 , does your graph
look like that you expect? (Discuss  what value DO you expect?) What is τ /τ0 for Φ0 = π /8 rad?
How about π /2 rad? What happens to τ as the amplitude of the oscillation approaches π ? Explain.
Note: The integral has some curious numerical...
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 Spring '11
 STEVEPOLLOCK
 mechanics, Mass, Work

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