question 11 (4 points)\n(01.08 hc)\nduring an experiment, the time of an object was measured every 20…

question 11 (4 points)\n(01.08 hc)\nduring an experiment, the time of an object was measured every 20 meters. each researcher measured the objects motion on different surfaces, noted as a, b, c, and d. their average data of the trials are shown below.\n| distance (cm) | 0 | 20 | 40 | 60 | 80 | 100 |\n| --- | --- | --- | --- | --- | --- | --- |\n| time a (s) | 0 | 5.23 | 10.11 | 14.68 | 18.54 | 23.36 |\n| time b (s) | 0 | 4.66 | 9.33 | 13.97 | 18.63 | 23.31 |\n| time c (s) | 0 | 3.57 | 7.44 | 11.32 | 16.98 | 23.28 |\n| time d (s) | 0 | 5.00 | 15.00 | 40.00 | 60.00 | 85.00 |\nwhich of the surfaces allowed the object to travel closest to a constant speed?\n a surface a\n b surface b\n c surface c\n d surface d
Answer
Explanation:
Step1: Recall speed - distance - time formula
Speed $v=\frac{d}{t}$, for constant speed, the ratio $\frac{\Delta d}{\Delta t}$ should be constant for equal - distance intervals. Here, $\Delta d = 20$ cm for each interval.
Step2: Calculate speed intervals for Surface A
For Surface A:
- From $d = 0$ to $d = 20$ cm, $v_1=\frac{20}{5.23}\approx3.82$ cm/s
- From $d = 20$ to $d = 40$ cm, $v_2=\frac{20}{10.11 - 5.23}=\frac{20}{4.88}\approx4.09$ cm/s
- From $d = 40$ to $d = 60$ cm, $v_3=\frac{20}{14.68 - 10.11}=\frac{20}{4.57}\approx4.38$ cm/s
- From $d = 60$ to $d = 80$ cm, $v_4=\frac{20}{18.54 - 14.68}=\frac{20}{3.86}\approx5.18$ cm/s
- From $d = 80$ to $d = 100$ cm, $v_5=\frac{20}{23.36 - 18.54}=\frac{20}{4.82}\approx4.15$ cm/s
Step3: Calculate speed intervals for Surface B
For Surface B:
- From $d = 0$ to $d = 20$ cm, $v_1=\frac{20}{4.66}\approx4.29$ cm/s
- From $d = 20$ to $d = 40$ cm, $v_2=\frac{20}{9.33 - 4.66}=\frac{20}{4.67}\approx4.28$ cm/s
- From $d = 40$ to $d = 60$ cm, $v_3=\frac{20}{13.97 - 9.33}=\frac{20}{4.64}\approx4.31$ cm/s
- From $d = 60$ to $d = 80$ cm, $v_4=\frac{20}{18.63 - 13.97}=\frac{20}{4.66}\approx4.29$ cm/s
- From $d = 80$ to $d = 100$ cm, $v_5=\frac{20}{23.31 - 18.63}=\frac{20}{4.68}\approx4.27$ cm/s
Step4: Calculate speed intervals for Surface C
For Surface C:
- From $d = 0$ to $d = 20$ cm, $v_1=\frac{20}{3.57}\approx5.60$ cm/s
- From $d = 20$ to $d = 40$ cm, $v_2=\frac{20}{7.44 - 3.57}=\frac{20}{3.87}\approx5.17$ cm/s
- From $d = 40$ to $d = 60$ cm, $v_3=\frac{20}{11.32 - 7.44}=\frac{20}{3.88}\approx5.15$ cm/s
- From $d = 60$ to $d = 80$ cm, $v_4=\frac{20}{16.98 - 11.32}=\frac{20}{5.66}\approx3.53$ cm/s
- From $d = 80$ to $d = 100$ cm, $v_5=\frac{20}{23.28 - 16.98}=\frac{20}{6.3}\approx3.17$ cm/s
Step5: Calculate speed intervals for Surface D
For Surface D:
- From $d = 0$ to $d = 20$ cm, $v_1=\frac{20}{5.00}=4.00$ cm/s
- From $d = 20$ to $d = 40$ cm, $v_2=\frac{20}{15.00 - 5.00}=\frac{20}{10}=2.00$ cm/s
- From $d = 40$ to $d = 60$ cm, $v_3=\frac{20}{40.00 - 15.00}=\frac{20}{25}=0.80$ cm/s
- From $d = 60$ to $d = 80$ cm, $v_4=\frac{20}{60.00 - 40.00}=1.00$ cm/s
- From $d = 80$ to $d = 100$ cm, $v_5=\frac{20}{85.00 - 60.00}=\frac{20}{25}=0.80$ cm/s
Step6: Compare the consistency of speeds
The speeds for Surface B have the least variation among the different intervals.
Answer:
B. Surface B