During take-off a 5kg model rocket, initially at rest, burns fuel for 4.6s causing its speed to increase from rest to 39m/s during this time despite experiencing a 60N drag.

The height is "89.61 m". A further explanation is given below.

Explanation:

According to the question,

Mass of rocket,

m = 5 kg

Time,

t = 4.6 s

Initial speed of rod

u = o m/s

Final speed,

v = 39 m/s

drag,

= 60 N

So,

⇒ acceleration,

⇒

Now,

The thrust will be:

⇒

⇒

⇒          

⇒                

⇒                          

⇒                          

The height will be:

⇒

divide the right side by the left side

0.024÷1.2=0.02 for example