Posted by **Matt** on Monday, October 29, 2012 at 1:18pm.

Homer Hickham and his buddies launched model rockets in the late 1950's when the US was trying to get a rocket into space. If homer launches a rocket from rest and its engine delivers a constance acceleration of 8.2 m/s^2 for 5.0seconds after which the fuel is used up by the rocket.

A) Find the maximum altitude reached by the rocket.

B) Find the total time the rocket is in flight (up and down)

- phyicis -
**Steve**, Monday, October 29, 2012 at 3:11pm
during burn:

v = 8.2t

v(5) = 41 m/s

h = 1/2 (8.2) t^2

h(5) = 102.5 m

So, after 5 seconds, the rocket is 102.5 meters up, with a speed of 41.0 m/s.

Now, only gravity provides acceleration, so

h = 102.5 + 41.0t - 4.9 t^2

h=0 when t = 10.382

max h when t = -41.0/-9.8 = 4.18

h(4.18) = 188.265

So, the rocket reaches a max height of 188.27m after 4.18 seconds of ballistic flight, and hits the ground again after 5.0+10.382 = 15.382 seconds have elapsed.

## Answer this Question

## Related Questions

- PHYSICS - Model rockets are lightweight rockets powered by very small engines. A...
- motion,physics - Model rockets are lightweight rockets powered by very small ...
- Physics - A typical model rocket has a mass of 50 g. Similarly, a typical "class...
- physics - Rockets A and B are fired straight upward from rest. Rocket A is ...
- Physics - A toy rocket is launched upwards from rest. The rocket engine will ...
- Physics - A model rocket launches with an initial velocity of 6 m/s, at an angle...
- physics - A model rocket is launched from rest with an upward acceleration of 5....
- physics - i need help figuring out what formaula to use for finding the final ...
- physics - A test rocket is launched vertically from ground level (y = 0 m), at ...
- physics - Model rocket engines are sized by thrust, thrust duration, and total ...