Processing Math: Done
Solution 19.5a
From Mechanics
(Difference between revisions)
(New page: <math>\begin{align} & v=\int{adt} \\ & \\ & =\int{\left( -kt \right)dt} \\ & \\ & =-\frac{k{{t}^{2}}}{2}+c \\ & \\ & t=0,\ v=20\ \Rightarrow \ c=20 \\ & \\ & v=20-\frac{k{{t}^{...) |
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& 5=20-\frac{k\times {{40}^{2}}}{5} \\ | & 5=20-\frac{k\times {{40}^{2}}}{5} \\ | ||
& \\ | & \\ | ||
- | & | + | & 800k=15 \\ |
& \\ | & \\ | ||
- | & k=\frac{15}{ | + | & k=\frac{15}{800}=\frac{3}{160} |
\end{align}</math> | \end{align}</math> | ||
+ | |||
+ | Note that substituting for <math>k</math> and <math>c</math> in the expression for <math>v</math> we get | ||
+ | |||
+ | <math>v=20-\frac{3{{t}^{2}}}{320}</math> |
Current revision
adt=
−kt
dt=−2kt2+ct=0
v=20
c=20v=20−2kt2 Usingt=40
v=5gives5=20−5k
402800k=15k=15800=3160
Note that substituting for