Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
An aeroplane flies level at a height of m. From a point on the ground its angle of elevation is . After seconds, it is . Find the distance it flew and its speed.
For an object at a fixed height , the horizontal distance at each sighting is . The distance moved is the difference of the two distances, and speed is the distance moved divided by the time. A width is a difference of two distances along one line.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The first distance. m.
Step 2. The second distance. m.
Step 3. The distance flown. m.
Step 4. The speed. m/s, which is about km/h.
Answer: m, at m/s.
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