$1.1.1.$ Figure$^{*)}$ shows a "blurred photograph" of a jet airplane in flight. The length of the airplane is 30 m, the length of its nose is 10 m. Determine from this "photograph" the speed of the airplane. The shutter exposure time is 0.1 s. The shape of the airplane is shown in the figure with a dashed line.
To find the velocity of the airplane it is necessary to determine the vector of its displacement for the time $T$, during which the shutter of the camera is open. Let us select the initial point $1$ in the photograph and determine the distance it will move during the time $T$. The length of the airplane must be subtracted from the total length of the photograph. Taking into account the scale, the modulus of displacement will be $$l=50-30 = 20 \;m$$ For the 0.1 s aiplane covered a distance of $20\; m$, which corresponds to velosity of $$\boxed{v = \frac{l}{T} = 200\; m/s}$$