P1112 Fall 2008 Homework #11 Due: the week of Nov 10-14 Reading: 9.1-9.4, 10.1-10.5 1. A single-stage rocket with initial mass (rocket plus fuel) m0 is accelerated from rest from a deep-space platform, where gravity is negligible. If the rocket burns its fuel in a time of 50 s, and the relative speed of the exhaust gas is 2100 m/s, so the mass is reduced to m, what must the mass ratio m0 /m be for a final speed of 8.0 km/s ? 2. A 20.0 km-projectile is fired at an angle 60 o above the horizontal and with a speed of 80.0 m/s. At the highest point of the trajectory the projectile explodes into two fragments with equal mass, one of which falls vertically with zero initial speed. Ignore air resistance. a) How far from the point of firing does the other fragment strike (level terrain) ? b) How much energy is released during the explosion ? 3. A flywheel with a radius of 0.3 m starts from rest and accelerates with a constant angular acceleration of 0.6 rad/s 2 . Compute the magnitude of the tangential
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