Kinematic Equations for a Rocket with Constant Acceleration: Homework Help

[physstudent1]

Homework Statement

A Rocket initially at rest on the ground accelerates straight upward from rest with constant net acceleration a, until time t_1 where fuel is exhausted.

Homework Equations

The Attempt at a Solution

I thought that putting these values into the kinematic equation

y = Vi(t) + 1/2*a*t^2 would be good but the answer is not 1/2(a)t^2 it is

H = .5(a)t + (.5*a^2*t^2)/g

 

[Chi Meson]

What is the problem asking for? Final height of the rocket? If so, remember that the rocket will still go up for a while after the fuel is exhausted, adding another distance to the one you have found. What's the initial velocity and what's the acceleration for the second part of this problem?

 

[physstudent1]

yes

yes it is asking for final height thank you I did not think of it still going up after running out of fuel I was thinking of it falling back down immediatly

 

[PhanthomJay]

Homework Statement

A Rocket initially at rest on the ground accelerates straight upward from rest with constant net acceleration a, until time t_1 where fuel is exhausted.

Homework Equations

The Attempt at a Solution

I thought that putting these values into the kinematic equation

y = Vi(t) + 1/2*a*t^2 would be good but the answer is not 1/2(a)t^2 it is

H = .5(a)t^2 + (.5*a^2*t^2)/g

see typo in red, now continue per Chi Meson's hint above.