The rocket's acceleration for the first 16 s is <u>27 m/s².</u>
The rocket starts from rest and experiences uniform upward acceleration a for a time t₁ = 16 s. During this period it travels upwards a distance s₁.
Use the equation of motion

Substitute s₁ for s, 0 m/s for u, 16 s for t =t₁, and write an equation for s₁ in terms of a.

The engines are switched off after 16 s and for the next 4 s, the rocket travels upwards under the acceleration due to gravity g, which is directed down wards.
Write an expression of the velocity v of the rocket at the end of 16 s.
Use the equation of motion,

Substitute 0 m/s for u and 16 s for t =t₁,

The rocket has a speed of v =16a at the beginning of its motion after its engines are switched off.
Determine the distance s₂ the rocket travels under the action of acceleration due to gravity g.
Use the equation of motion

Substitute s₂ for s, 16 a for u, 4 s for t and -9.8 m/s² for g.

The total distance s traveled by the rocket is given by,

Add equations (1) and (3) and substitute 5100 m for s.

The acceleration of the rocket in the first 16 s is <u>27 m/s^2(2sf)</u>