course phy 201
9/28 at 10:00
A ball is tossed upward with an initial velocity of 25 meters / second. Assume that the acceleration of gravity is 10 m/s^2 downward. •What will be the velocity of the ball after one second?
answer/question/discussion: v=v0+at v = 25-10(1) v = 15m/s
• What will be its velocity at the end of two seconds?
answer/question/discussion: v=v0+at v=25-10(2) v = 5m/s
• During the first two seconds, what therefore is its average velocity?
answer/question/discussion: (25+5) / 2= 15m/s
• How far does it therefore rise in the first two seconds?
answer/question/discussion: ds = ( v0+vf) / 2 * t ds = 30 meters
• What will be its velocity at the end of a additional second, and at the end of one more additional second?
answer/question/discussion: v=v0 + at v = 25-10(3) V= -5m/s
v=v0 + at v = 25-10(4) V= -15m/s
• At what instant does the ball reach its maximum height, and how high has it risen by that instant?
answer/question/discussion: y = v^2-v0^2/2a y =25^2 / 2(10) 31.25 meters
• What is its average velocity for the first four seconds, and how high is it at the end of the fourth second?
answer/question/discussion: v avg. = (v0+vf) /2 =25+(-15) / 2 = -5m/s
• How high will it be at the end of the sixth second?
answer/question/discussion: 0 since the ball will be on the ground after the time of 5 seconds.
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Good, but be sure you turn each cq problem in using the form from which you get the problem.