volume_mute

An object falling from rest

publish date2022/08/06 01:25:00 GMT+10

volume_mute

An object falling from rest reaches a speed of ft/s (or m/s) after falling 5 seconds.  (Ignore air resistance.)  At this time it has fallen ft (or 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


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