Answer:
S = 11.025 m
Explanation:
Given,
The time taken by the pebble to hit the water surface is, t = 1.5 s
Acceleration due to gravity, g = 9.8 m/s²
Using the II equations of motion
S = ut + 1/2 gt²
Here u is the initial velocity of the pebble. Since it is free-fall, the initial velocity
u = 0
Therefore, the equation becomes
S = 1/2 gt²
Substituting the given values in the above equation
S = 0.5 x 9.8 x 1.5²
= 11.025 m
Hence, the distance from the edge of the well to the water's surface is, S = 11.025 m
Answer and Explanation
Arranging the measured values in increasing order;
4.3s, 4.6s, 4.6s, 4.8s, 5.1s, 5.8s
The two outliers are obviously 4.3s and 5.8s; An outlier is a value in a statistical sample which does not fit a pattern that describes most other data point. Outliers make the average value complicated. So, it is usually better for data to be precise with data points spreading out around a small area.
So, the mean is the average of the four remaining data points after removing the outliers.
Mean = (4.6 + 4.6 + 4.8 + 5.1)/4
Mean = 4.775s
So, the value recorded should be 4.775s, 4.78s or 4.8s depending on the number of decimal places allowed.
QED!
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