PHY201
Your 'cq_1_8.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** **
Seed Question 8.1
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:
v0 = 25m/s
a= 10m/s/s
v = v0 +at = 25m/s + -10m/s/s * 1s = 25m/s – 10m/s = 15m/s
• What will be its velocity at the end of two seconds?
answer/question/discussion:
v = v0 +at = 25m/s + -10m/s/s * 2s = 25m/s – 20m/s = 5m/s
• During the first two seconds, what therefore is its average velocity?
answer/question/discussion:
vavg = (vf + v0)/2 = (5m/s +25m/s)/2 = 30m/s / 2 = 15m/s
• How far does it therefore rise in the first two seconds?
answer/question/discussion:
y = v0t + at^2 = 25m/s * 2s + -10m/s/s * 2s^2 = 50 – 20 = 30m
• What will be its velocity at the end of an additional second, and at the end of one more additional second?
answer/question/discussion:
v = v0 + at = 25m/s + -10m/s/s * 3s = 25m/s – 30m/s/s = -5m/s
v = v0 + at = 25m/s + -10m/s/s * 4s = 25m/s – 40m/s = -15m/s
• At what instant does the ball reach its maximum height, and how high has it risen by that instant?
answer/question/discussion:
t = - vo/a = -25m/s / -10m/s/s = 2.5s
Y = (v^2 – v0^2)/ 2a = ( 0 – 25m/s^2) / 2 * -10m/s/s = -625/-20 = 31.25m
• 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:
vavg = (vf + v0)/2 = (-15m/s + 25m/s)/2 = 10m/s /2 = 5m/s
y = v0t + ½ at^2 = 25m/s * 4s + ½ *-10m/s/s * 4s^2 = 100 + ½ * -160 = 100-80 = 20m
• How high will it be at the end of the sixth second?
answer/question/discussion:
v = v0 + at = 25m/s + -10m/s/s * 6s = 25m/s – 60m/s = -35m/s
y = v0t + ½ at^2 = 25m/s * 6s + ½ *-10m/s/s * 6s^2 = 150 + ½ * -360 = 150- 180 = -30m
** **
2hours
** **
Excellent work.