sorry to repost (again) but I'm not understanding how to solve this:
A rocket is launched at an angle of 42◦ above the horizontal with an initial speed of 76 m/s. It moves for 9 s along its initial line of motion with an acceleration of 29 m/s^2. At this time
its engines fail and the rocket proceeds to move as a projectile.
The acceleration of gravity is 9.8 m/s^2.
a.) Find the maximum altitude reached by the rocket.
b.) What is its total time of flight?
c.) What is its horizontal range?
I know how to find these with constant acceleration (I think) but with the increasing acceleration I'm not sure.
a.) 3837.91 m
b.) 59.9965 s
c.) 14152.7 m
A tutor told me earlier I have to break this down into 2 parts: with increasing acceleration (engines on) and after (engines off) but I'm not sure how to do the first (engines on) part.
Need to know how to solve, thank you.
Physics - John, Monday, September 6, 2010 at 11:49pm
double post, sorry.
Physics - drwls, Monday, September 6, 2010 at 11:58pm
Acceleration is not increasing with engines on. It is constant.
When the engines are on,
Y = 76 sin42 t + (1/2)(29 sin 42)t^2
X = 76 cos42 t + (1/2)(29 cos 42)t^2
Use t = 9 s to find out the location and speed at burnoout. Then write a new equation for the position after that. Assume the earth is flat and that g is constant. For a rocket designed to launch satellites or escape the earth, these are only approximations.