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Vertical motion

Average velocity

Using the values of the above table, we determine the average velocity in each time interval. The values obtained for all intervals are collected in the table below.

interval (s)	average velocity (m/s)
0.0 - 0.1	19.0
0.1 - 0.2	17.2
0.2 - 0.3	15.6
0.3 - 0.4	14.0
0.4 - 0.5	12.6
0.5 - 0.6	11.2
0.6 - 0.7	10.0
0.7 - 0.8	8.8
0.8 - 0.9	7.6
0.9 - 1.0	6.5
1.0 - 1.1	5.4
1.1 - 1.2	4.4
1.2 - 1.3	3.4
1.3 - 1.4	2.4
1.4 - 1.5	1.3
1.5 - 1.6	0.4
1.6 - 1.7	-0.5
1.7 - 1.8	-1.6
1.8 - 1.9	-2.5
1.9 - 2.0	-3.5
2.0 - 2.1	-4.4
2.1 - 2.2	-5.4
2.2 - 2.3	-6.2
2.3 - 2.4	-7.1
2.4 - 2.5	-7.9
2.5 - 2.6	-8.8
2.6 - 2.7	-9.5
2.7 - 2.8	-10.2
2.8 - 2.9	-11.0
2.9 - 3.0	-11.6
3.0 - 3.1	-12.2
3.1 - 3.2	-12.8
3.2 - 3.3	-13.3
3.3 - 3.38	-13.8

A graphical representation for the table can be found here

We observe that the decrease of the average velocity is not as constant as in the case of the metal ball. Only in the intervals from t=1.0 s to t=2.0 s the average velocity decreases on average about 1 m/s in each subsequent interval. But before t=1.0 s we have decreases of subsequently 1.8 m/s, 1.6 m/s, 1.6 m/s, 1.4 m/s, 1.2 m/s, 1.2 m/s, 1.2 m/s and 1.1 m/s, whereas after t=2.0 s the decreases are subsequently 1.0 m/s, 0.8 m/s, 0.9 m/s, 0.8 m/s, 0.9 m/s, 0.7 m/s, 0.7 m/s, 0.8 m/s, 0.6 m/s, 0.6 m/s, 0.6 m/s and 0.5 m/s.

We may safely conclude that the deceleration is not constant for the plastic ball as it was for the solid metal ball.

air resistance