Mike D. answered • 10/04/21
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Use s = ut + 0.5at2
u = 0 m/s
a = 9.81 m/s/s
The 8th second is from t=7 to t=8
So the required distance is s(8) - s(7). [ substitute t=8 into s, to find s(8) ]
Mike D.
s = distance fallen (m), u = initial speed (=0 because it starts from rest), a = acceleration m/s/s (will be 9.81 m/s/s due to gravity), t = time after it starts to fall in s. So you need s after 8 seconds minus s after 7 seconds.
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10/12/21
Vince Arvi S.
So that would mean s8 - s7 = s1?
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10/13/21
Mike D.
No. s(8) is the distance fallen after 8 seconds. s(1) is the distance fallen after 1 second. s(8) - s(7) is the distance fallen between 7 and 8 seconds ie in the 8th second.
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10/13/21
Vince Arvi S.
Im so sorry, i still dont quite understand how to get the time :(
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10/13/21
Mike D.
1st second is from t=0 to t=1, 2nd second is from t=1 to t=2, .. so 8th second is from t=7 to t=8. Try and see the pattern, I have broken it down as much as I can for you now you need to try and understand it.
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10/13/21
Vince Arvi S.
Alright, thank you!
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10/14/21
Vince Arvi S.
OH! ok ok i get it, thank you so much for your patience!
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10/14/21
Vince Arvi S.
Sorry i dont get it, mind if you explain it to me please?10/11/21