Unformatted text preview: kg projectiles are launched identically. The first projectile lands 80 m away.
The second explodes in flight, breaking into two parts which land simultaneously. One part,
weighing 0.10 kg, lands 60 m away, between the launch site and the first projectile. How far
away will the rest of it land? 0 60 m 80 m The center of mass of the second projectile will land where the first projectile landed, so This gives
To see the result quickly, note that the second part is twice as
heavy as the part at 60 m, so it must be half the distance from the center of mass: 10 m
beyond it. (b) [4pt] A wheel with moment of inertia rolls without slipping. What fraction of its kinetic energy is rotational? The translational energy is
if and the rotational energy is , which is true when there is no slipping.
so the fraction of rotational energy is Note that if this ratio is always . The total energy is 5 (c) [4pt] The Saturn V rocket used for the Apollo missions had a mass of
kg, and its
first stage burned
kg of propellant (a type of kerosene plus liquid oxygen) in 150 s.
What was the minimum speed at which...
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