course PHY 121
For each situation state which of the five quantities v0, vf, `ds, `dt and a are given, and give the value of each. •A ball accelerates uniformly from 10 cm/s to 20 cm/s while traveling 45 cm.
A
###20cm/s – 10cm/s = 10cm/s
45cm / 10cm/s =4.5cm/s
The quantities you are give here are
10 cm/s
20 cm/s
45 cm.
Is 10 cm/s a value of v0, vf, `ds, `dt or a?
Is 20 cm/s a value of v0, vf, `ds, `dt or a?
Is 45 cm a value of v0, vf, `ds, `dt or a?
This would answer the question implicit in 'state which of the five quantities v0, vf, `ds, `dt and a are given, and give the value of each'.
Similar answers would be appropriate on the other two situations below.
answer/question/discussion:
• A ball accelerates uniformly at 10 cm/s^2 for 3 seconds, and at the end of this interval is moving at 50 cm/s.
Vf
###This was ‘ds.
###10cm/s^2 * 3 = 30cm/s
###50cm/s + 30cm/s=80cm/s / 2 = 40cm/s
answer/question/discussion:
• A ball travels 30 cm along an incline, starting from rest, while accelerating at 20 cm/s^2.
Ds
###This was not directly reasoned out.
answer/question/discussion:
Then for each situation answer the following:
• Is it possible from this information to directly determine vAve?
Yes
###No for the 2nd and 3rd situation.
answer/question/discussion:
• Is it possible to directly determine `dv?
No
###Yes for the 1st and 2nd one.
"
Better start over on this one. See my notes above, which should clarify what is being asked here.