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Chapter 7, Part 2. October 21, 2005. 60. F. F. heavy. 35. light. 0. 0.
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Chapter 7, Part 2 October 21, 2005
60 F F heavy 35 light 0 0 Two boxes, one heavier than the other, are initially at rest on a horizontal frictionless surface. The same constant force F acts on each one for exactly 1 second. Which box has more momentum after the force acts? • The lighter one. • The heavier one. • Both the same.
60 F F heavy 35 light 0 0 For the same situation as the previous problem, which box has the larger velocity after the force acts? • The lighter one. • The heavier one. • Both the same.
60 35 0 0 Consider the following “Geophysical weapon”: what would happen if the entire country of China jumped at once? • The earth’s orbit would be measurably perturbed. • Nothing since the resulting momentum of the earth would be so much less than the momentum of the people • Nothing since the resulting velocity of the earth would be so much less than the velocity of the people
60 35 0 0 A racquet ball is placed on top of a basketball and both are dropped from height h above the ground. The two balls collide as the basketball recoils from the ground. The resulting height of the racquet ball after the collision is • Equal to h. • Less than h. • Greater than h. Just as basketball recoils
Answers 3 – both the same, see above 1 – the lighter one, p=mv, if same p then small m means big v 3 – p is same for both, but Mearth is huge, so tiny v 3 - greater than, little guy gets a boost from the big guy (basis of supernova explosions, gravitationally inward falling outer material crashes into outward exploding inner material creating tremendous velocities – populates the universe with the various elements)