Posted by **ibo** on Wednesday, September 29, 2010 at 2:52pm.

A rocket rises vertically from a point on the ground that is 100m from an observer at ground level. The observer notes that the angle of elevation is increasing at a rate of 12∘per second when the angle of elevation is 60∘. Find the speed of the rocket at that instant. Hint: remember to use radians.

- calculus -
**Reiny**, Wednesday, September 29, 2010 at 4:49pm
make a diagram.

you should have a right-angled triangle, where the angle of elevation is Ø, the adjacent is 100 and the opposite is h, the height of the rocket.

tanØ = h/100

h = 100tanØ

dh/dt = 100sec^2 Ø (dØ/dt)

when Ø = 60° or π/3 rad

dØ/dt = 12°/sec or 12π/180 rad/sec = π/15 rad/sec

sub into the dh/dt equation and you are done

## Answer This Question

## Related Questions

- geometry - Observer on ground is x meters from base of launch pad of rocket, ...
- Calculus angle of elevation - An observer is 31m above the ground floor of a ...
- differential calculus - ANGLE OF ELEVATION A balloon rises at a rate of 4 meters...
- Calculus - An observer is 23m above the ground floor of a large hotel atrium ...
- calculus - An observer is 20 m above the ground floor of a large hotel atrium ...
- Calculus - A rocket is fired vertically into the air at the rate of 6 miles/min...
- Calculus - A balloon leaves the ground 500 feet away from an observer and rises ...
- Calculus - An observer is 36m above the ground floor of a large hotel atrium ...
- Calculus angle of elevation with elevator - An observer is 20m above the ground ...
- what is the rate of change of the angle of eleva - An observer is 20 m above the...

More Related Questions