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Unformatted text preview: Engineering Mechanics - Dynamics Chapter 12 Solution:
2π z' = θ h θ' 2π 2 v= z' + ( rθ' ) = ⎛ h ⎞ + r2 θ'
⎝ 2π ⎠ θ' = v θ' = 1.304 2 2 2 rad
s ⎛ h ⎞ + r2
⎝ 2π ⎠
a = −r θ' 2 a = 2.55 m
2 s Problem 12–154
A cameraman standing at A is following the movement of a race car, B , which is traveling along
a straight track at a constant speed v. Determine the angular rate at which he must turn in order
to keep the camera directed on the car at the instant θ = θ1.
v = 80
Solution: ft θ 1 = 60 deg s a = 100 ft θ = θ1 a = r sin ( θ )
0 = r' sin ( θ ) + rθ' cos ( θ )
x = r cos ( θ )
vx = −v = r' cos ( θ ) − rθ' sin ( θ )
r = 1 ft r' = 1 ft
s θ' = 1 rad
a = r sin ( θ )
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- Spring '08