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What am I doing wrong with this physics question?
Here's the question:
The observation deck of a tower is 190 m above the street. Determine the time required for a penny to drop from the deck to the street below. (Answer given: 6.22 s.)
I used (excuse the lack of deltas and vector symbols): d=v{i}t + 2a(t)^2. Rewriting the equation, I had
t= sqrt(d/2a) which gave me 3.11 s, half of their answer. Where did I go wrong? (Or do they have it wrong?)
3 Answers
- remowlmsLv 71 decade agoFavorite Answer
t^2 = (2d)/(gf)
t^2 = (2x190)/(9.8*1)
t^2 = 38.7755
t = sqrt(38.7755)
t = 6.2270 sec
Source(s): The original formula you have wrong. It should be d = v(i)t +(a(t^2))/2. Your formula that you rewrote should have been t = sqrt(2d/a). Hope that helps - Cheers! - billrussell42Lv 71 decade ago
d = d₀ + ½at²
a = 9.81 m/s²
d₀ = 0
190 = ½(9.81)t²
t² = 380/9.81 = 38.74
t = 6.22
- Anonymous1 decade ago
ask your teacher. man i hate physics im quiting it soon..
