Answer:
<em>1988.05 rad/s^2</em>
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Explanation:
The angular speed of the optical disk ω = 998.0 rad/s
the time taken to come to rest t = 0.502 s
The magnitude of the average angular acceleration ∝ = ω/t
∝ = 998.0/0.502 = <em>1988.05 rad/s^2</em>
The answer is the second choice
3.
a)
r = distance of each mass in each hand from center = 0.6 m
m = mass of each mass in each hand = 2 kg
v = linear speed = 1.1 m/s
L = combined angular momentum of the masses = ?
Combined angular momentum of the masses is given as
L = 2 m v r
L = 2 (2) (1.1) (0.6)
L = 2.64 kg m²/s
b)
v' = linear speed when she pulls her arms = ?
r' = distance of each mass from center after she pulls her arms = 0.15 m
Using conservation of momentum , angular momentum remains same, hence
L = 2 m v' r'
2.64 = 2 (2) (0.15) v'
v' = 4.4 m/s
