MHB 3-42 Where on ground (relative to position of the helicopter

karush
Gold Member
MHB
Messages
3,240
Reaction score
5
ok this is out of an old textbook and possibly already posted here so..

A movie stunt woman drops from a helicopter that is 30.0 m above the ground and moving with a constant velocity whose components are 10.0 m/s upward and 15.0 m/s horizontal and toward the south. Ignore air resistance.
[a.] Where on the ground (relative to the position of the helicopter when she drops) should the stunt woman have placed the foam mats that break her fall?

well so far... but not sure
$y=y_0+V_0 yt+.5A yt^2$
$0=30+10t[-.5(9.8)t^2]$
so $0=-4.9t^2+10t+30$

later [b.] Draw x-t, y-t, v ft, and v y-t graphs of the motion
 
Last edited:
Mathematics news on Phys.org
$\Delta x = v_{x_0} \cdot t$

$\Delta y = v_{y_0} \cdot t - \dfrac{1}{2}gt^2$

solve the quadratic for $t$, then calculate $\Delta x$
 
ok not sure why this doesn't render but it my understanding of the problem
\begin{tikzpicture}[xscale=.4,yscale=.2]
\draw [very thick] (-1,0) -- (20,0);
\draw [thin] (0,0) -- (0,30);
\draw [dashed][->] (0,30) -- (15,30);
\draw [dashed][->] (0,30) -- (0,40);
\draw [dashed][->] (0,30) -- (15,40);
\node
at (0,30) {30 m};
\node
at (15,30) {15 m/s};
\node [above] at (0,40) {10 m/s};
\end{tikzpicture}
at (15,30) {15 m/s};
\node [above] at (0,40) {10 m/s};
\end{tikzpicture}​
 
Last edited:
$\dfrac{1}{2}gt^2 - v_{y_0} \cdot t + \Delta y = 0 \implies t = \dfrac{v_{y_0} + \sqrt{(v_{y_0})^2 - 2g\Delta y}}{g}$

for the given values, $t \approx 3.7 \, sec$

$\Delta x = v_{x_0} \cdot t \approx 55.5 \, m$ due South of the drop position.
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.
Back
Top