The angle of elevation of a jet plane from a point A on the ground 60 ...
Problem:
The angle of elevation of a jet plane from a point A on the ground 60 degree.After a flight of 15 seconds the angle of elevation changes to 30 degrees.If the jet plane is flying at a constant height of 1500√3m,find the speed of the jet plane?
Solution:
Let's consider the given problem step-by-step:
Step 1: Draw a diagram
Draw a diagram to represent the given situation. Label the relevant parts with the given values and the unknowns.
![jet_plane_diagram.png](https://edurev-media.netlify.app/image/202112/jet_plane_diagram.png)
Step 2: Derive equations
Using trigonometry, we can derive two equations:
- tan(60) = height / distance1
- tan(30) = height / distance2
where height is the constant height of the jet plane, and distance1 and distance2 are the distances travelled by the jet plane in the two different positions.
Step 3: Solve for unknowns
Using the two equations above, we can solve for the two unknowns:
- distance1 = height / tan(60)
- distance2 = height / tan(30)
Using the formula for average speed:
average speed = total distance / total time
We can calculate the total distance as:
total distance = distance1 + distance2
The total time is given as 15 seconds. Therefore, we can calculate the average speed of the jet plane as:
average speed = (distance1 + distance2) / 15
Step 4: Simplify
Substituting the values of distance1 and distance2, we get:
average speed = (height / tan(60) + height / tan(30)) / 15
Simplifying further, we get:
average speed = height(2 / √3 + 1) / 15
Substituting the value of height as 1500√3m, we get:
average speed = 500(2 + √3) m/s
Step 5: Final Answer
Therefore, the speed of the jet plane is 500(2 + √3) m/s.