course PHY 121
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?
25m/s / 10m/s^2 = 2.5m/s
###25m/s is positive because it is upward and 10m/s^2 would be negative because it is downward.
###So after 1s it would be 25m/s-10m/s=15m/s
answer/question/discussion:
What will be its velocity at the end of two seconds?
2.5m/s * 2 = 5.0m/s
###This should be 25m/s -10m/s=15m/s -10m/s= 5m/s
answer/question/discussion:
During the first two seconds, what therefore is its average velocity?
5.0m/s * 2s = 10m/s
###This would be 25m/s + 15m/s=40m/s / 2=20m/s *1s=20m
answer/question/discussion:
How far does it therefore rise in the first two seconds?
25m/s 10m/s = 15m/s
###This should be 15m/s * 2= 30m
answer/question/discussion:
What will be its velocity at the end of a additional second, and at the end of one more additional second?
###This should be 5m/s * 4s= 20m
answer/question/discussion:
At what instant does the ball reach its maximum height, and how high has it risen by that instant?
###25m/s 10m/s^2 = 2.5s
answer/question/discussion:
What is its average velocity for the first four seconds, and how high is it at the end of the fourth second?
###12.5m/s * 2.5s = 31.25m
answer/question/discussion:
How high will it be at the end of the sixth second?
###This should be -5m/s * 6s=-30m
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You aren't identifying your quantities correctly.
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The definition of average velocity is average rate of change of position with respect to clock time, which is equal to
ave velocity = (change in position) / (change in clock time).
In symbols we would write this
vAve = `ds / `dt.
Suppose now that something travels at 3 cm/s for 5 seconds.
Is 3 cm/s the ave velocity, the change in position, or the change in clock time?
answer:
Is 5 seconds the ave velocity, the change in position, or the change in clock time?
answer:
If you know the change in position and the change in clock time, how do you find the average velocity?
answer:
If you know the change in position and the average velocity, how do you find the change in clock time?
answer:
If you know the change in clock time and the average velocity, how do you find the change in position?
answer:
Is 3 cm/s the value of vAve, `ds or `dt?
answer:
Is 5 s the value of vAve, `ds or `dt?
answer:
If you know `ds and `dt, how do you find vAve?
answer:
If you know vAve and `dt, how do you find `ds ?
answer:
If you know `ds and vAve, how do you find `dt?
The definition of average acceleration is average rate of change of velocity with respect to clock time, which is equal to
ave acceleration = (change in velocity) / (change in clock time).
In symbols we would write this
aAve = `dv / `dt.
Suppose now that something something accelerates at 7 cm/s^2 for 3 seconds.
Is 7 cm/s^2 the ave acceleration, the change in position, or the change in clock time?
answer:
Is 3 seconds the ave acceleration, the change in position, or the change in clock time?
answer:
If you know the change in velocity and the change in clock time, how do you find the average acceleration?
answer:
If you know the change in velocity and the average acceleration, how do you find the change in clock time?
answer:
If you know the change in clock time and the average acceleration, how do you find the change in velocity?
answer:
Is 7 cm/s the value of aAve, `dv or `dt?
answer:
Is 3 s the value of aAve, `dv or `dt?
answer:
If you know `dv and `dt, how do you find aAve?
answer:
If you know aAve and `dt, how do you find `dv?
answer:
If you know `dv and aAve, how do you find `dt?
answer: