(due in 1 hour) a rocket of mass m is launched straight up with thrust f⃗ thrust.
a. find an expression for the rocket's speed at height h if air resistance is neglected. express your answer in terms of the variables fthrust, m, h, and appropriate constants.
b. the motor of a 340 g model rocket generates 10 n thrust. if air resistance can be neglected, what will be the rocket's speed as it reaches a height of 86 m ?

From the statement, since rocket was launched so this means that it start from zero, hence initial velocity is zero. 
Since the rocket was launched vertically straight up, the force acting on this motion is gravity.

 
A. The acceleration of the motion is then given by:

a= F/m - g 

Then we can use the general equation:

V^2 = Vo^2 + 2*a*h

where V is final velocity, Vo is initial velocity, a is acceleration, h is height 

Since we know that Vo = 0, so 

V^2 = 2*a*h 

V^2 = 2 (F/m – g) h
V = sqrt [2 h (F/m – g)]

B. Given that:

h = 86 m

F = 10 N

m = 340 g = 0.34 kg

Find for V:

V = sqrt [2 * 86 (10 / 0.34 – 9.8)]

V = 58.08 m/s

d) physical means can be used to separate the components of air.