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An object falling from rest
publish date: 2022/08/06 01:25:00 GMT+10
An object falling from rest reaches a speed of (1) ft/s (or (2) m/s) after falling 5 seconds. (Ignore air resistance.) At this time it has fallen (3) ft (or (4) m).
Correct Answer
(1) 160
(2) 49
(3) 400
(4) 122.5
Explanation
Calculate the final speed by multiplying 5 by acceleration
s = t * a = 5 * a
Calculate the total distance by this equation
d = 1/2 at2
| Ft | Meter | |
| speed | 5*9.8 = 49 | 32 * 5 = 160 |
| distance | 1/2 * 9.8 * 52 = 122.5 | 1/2 * 32 * 52 = 400 |
Reference
Basic Physics: A Self-Teaching Guide