Let A be the
stationary helicopter
and F be the reflection
of the helicopter, CB be
the level of lake and D
be the point 100 m
above it
Let AB = height of
helicopter = x m
then BF = x m
BE = DC = 100 m
Let DE = BC = y m
AE = AB – EB = (x – 100) m
and EF = BF + EB = (x + 100) m
Or
The angle of elevation of an aeroplane from a point on the ground is 60°. After a flight of 15 seconds, the angle of elevation changes to 30°. If the aeroplane is flying at a constant height of 1500m, find the speed of the aeroplane.
Mathematics 2008 Question Papers Class X | |||||||
Delhi | Outside Delhi | Compartment Delhi | Compartment Outside Delhi | ||||
All Sets(PDF) | Set 1 | Set 1 | |||||
Set 2 | Set 2 | ||||||
Set 3 | Set 3 |