Question

A test rocket is launched vertically from ground level (y = 0 m), at time t = 0.0 s. The rocket engine provides constant upward acceleration during the burn phase. At the instant of engine burnout, the rocket has risen to 49 m and acquired a velocity of 30 m/s How long did the burn phase last?

Answer 1

I: x = 1/2at²
II: v = at

I+II: x = 1/2a(v²/a²) = 1/2 v²/a

a = 1/2 v²/x

v = 30
x = 49

Answer 2

Answer:

Explanation:

As the rocket was going up with acceleration due to upthrust by engine we will not take the effect of gravitational acceleration g separately.