Calvin     Home Page Homeworks Lab Projects Log Out     Help   Version 2.31i, Aug 15, 2004 Copyright © 2003-2004 Gradiance Corporation

Gradiance Online Accelerated Learning  Homework Assignment Submitted Successfully.  Submission number:  42723  Submission certificate:  JB412613  Submission time:  13 Dec 2004 10:23:56 PST (GMT-8:00)  Title:  General Science/Math      Positive points per question:  3.0      Negative points per question:  1.0      Number of questions:  4      Your score:  4.0     Description:                                      A collection of questions from High-School/Early College analytic subjects. This assignment shows an ongoing homework, where students see the choice explanations every time they make an incorrect answer, but they do not get to see the full explanations.  1. A projectile is fired with an initial velocity in the x (horizontal) direction of 1000 ft./sec. and an initial velocity in the y (vertical) direction of 500 ft./sec. Write the equation that gives y as a function of x. Demonstrate the correctness of your solution by selecting, from the list below, the (x,y) point that is on the trajectory of the projectile.      a)  x = 2000; y = 936.    b)  x = 4000; y = 1488.    c)  x = 1000; y = 500.    d)  x = 1000; y = 468.     Answer submitted:  d)     Your answer is incorrect.     You may have the right idea, but it could be that you are forgetting a factor of 2 in computing the effect of the acceleration of gravity on the position.    2. A farmer has 100 yards of fence, with which to create a rectangular cow pasture along a straight river. The side facing the river does not have to be fenced, but the other three sides do. Find, in feet, the sides and area of the pasture that has the largest possible area. Then identify the correct statement from the list below.      a)  One side is 75 ft. long    b)  The area is 5625 sq. ft.    c)  One side is 100 ft. long    d)  One side is 200 ft. long     Answer submitted:  a)     You have answered the question correctly.    3. Suppose we try to estimate the area under the curve f(x) = x2, from x=0 to x=1, using the trapezoidal rule. The error in the estimate decreases as we use more trapezoids. Suppose we use k trapezoids; i.e., we use the values of f(x) at x=0, x=1/k, x=2/k,...,x=(k-1)/k, x=1. Compute the error in the estimate for k=2, k=3, and k=4. Then, identify the correct statement below.      a)  For k=4, the error is 1/96.    b)  For k=3, the error is 0.    c)  For k=2, the error is 5/12.    d)  For k=2, the error is 3/8.     Answer submitted:  a)     You have answered the question correctly.    4. Which of the following elements binds most strongly with Oxygen?      a)  Aluminum    b)  Silicon    c)  Hydrogen    d)  Nitrogen     Answer submitted:  a)     Your answer is incorrect.     Oxygen has a -2 valence (it is missing two electrons in its outermost shell). Aluminum, with 3 electrons and 5 holes in its outermost shell, will bind with Oxygen, but the bond is not as strong as it would be for elements with fewer electrons in the outermost shell.