elli

This page lists questions and answers that were posted by visitors named elli.

Questions

The following questions were asked by visitors named elli.

Answers

The following answers were posted by visitors named elli.

for a: 41.67
11 years ago
for b: F - f_k = ma F - f_k = mdv/dt (F - f_k)dt = mdv ∫(F - f_k)dt = ∫mdv mv_f - mv_i = (β/3)(t_f)^3 - (f_k)t_f - [(β/3)(t_i)^3 - (f_k)t_i] [Note: v_i = 0 and t_i = 0] mv_f = (β/3)(t_f)^3 - (f_k)t_f v_f ≅ 10.83, but that's not the answer, so any suggesto...
11 years ago
have you check your data, because for a got a green mark, so A is ok, but b and c were not. There might be some where m = 3 and beta=1.2
11 years ago
It might be better to indicate the equation rather than answers, because the data changes. So, we have: F-ff=ma (1) I.alpha=F.R-ff.r (2) and we have two equation ant variables. but alpha is a/R or a/r
11 years ago
error, so we'll have: F-ff=m.a -> ff=F-m.a (1) I.alpha=F.r+ff.R (2) alpha=a/R then: a=F.(R+r)/(I/R+m.R) a=positive ff=negative, and for a got green mark, but not for f, should I write ff with "-" or just the value? I got a=16.3 f=-4.6
11 years ago
from a we have: N=f.d/Vs for b: N=f.(d+v.t)/Vs dN/dt=f.v/Vs
11 years ago
but, how did you do with D)???
11 years ago
so I risked one chance and got: a) N=f.d/Vs b) dN/dt=f.Vobs/Vs c) f'=f(1-Vobs/Vs) and I thought for d: f'=f.Vs/(Vs-Vwind) but it's not right, I'll assume f' have to be bigger since, Vwind goes from source to observer.. but well, any suggestions?
11 years ago
so, no more suggestions for b and c of initial question? and Mets, check the videos from week 13.
11 years ago
my values were right, just had to write the value of f without the -. Now, anyone has checked the falling ruler???
11 years ago
so... no ideas for this problem???
11 years ago
answers depend on the values we have so, for A F = dp/dt -> dp = Fdt ∫dp = ∫Fdt p_f - p_i = ∫βt²dt p_f - 0 = (β/3)(t_f)^3 - (β/3)(t_i)^3 for b: F - fk = m.a F - fk = m.dv/dt (F - fk)dt = m.dv ∫(F - f_k)dt = ∫m.dv m.vf - m.vi = (β/3)(tf)^3 - (fk)tf - [(β/3...
11 years ago
did you ever figure it out?
8 years ago