1.1.1. Figure$^{*)}$ shows a "blurred photograph" of a jet airplane in flight. The length of the airplane is $30 \text{ m}$, the length of its nose is $10 \text{ m}$. Determine from this "photograph" the speed of the airplane. The shutter exposure time is $0.1 \text{ s}$. The shape of the airplane is shown in the figure with a dashed line.
Solution
1.1.1. Airplane photo
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 $$l=50-30 = 20 \text{ m}$$ For the $0.1 \text{ s}$ aiplane covered a distance of $20\text{ m}$, which corresponds to velosity of $$\boxed{v = \frac{l}{T} = 200\text{ m/s}}$$
