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Sat 27 Jan, 2007 10:21 am
1. You've just the $1 million cash lottery, and you go to pick up the prize. What is the approximate weight of teh cash if you request payment in (a) quarters (b) dollar bills?
2. Suppose 1.0 cubic meter of oil is spilled into the ocean. Find the area of the resulting slick, assuming that it is one molecule thick, and that each molecule occupies a cube 0.50 µm on a side.
3. A model rocket blasts off and moves upward with an acceleration of 12 m/s² until it reaches a height of 26 m, at which point its engine shuts off and it continues its flight in free fall.
(a)What is the maximum height attained by the rocket?
(b) What is the speed of the rocket just before it hits the ground?
(c) What is the total duration of teh rocket's flight?
Is there anyone who can show me how to start it off or how to work the problems? Thankyou in advance!
1. You need to know what a quarter and a dollar bill weigh.
2. How many of these little cubes comprise the total volume of spilled oil? How much ocean area does each occupy?
3. Using formulas you should already know, you should be able to calculate the velocity at 26m and how long it took to get there. Then calculate the max height based on this "initial" velocity with the new (gravitational) acceleration. Calculating speed at height=0 is easy if you know the max height. To the time you already calculated, add the time it takes to go from 26m to 0m based on gravitational acceleration and the "initial" velocity.
By "initial" velocity, I mean the velocity reached at 26m which is the initial velocity when the only force acting on the rocket is gravitational.
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