Question

A rocket ship starts from rest and turns on its forward booster rockets, causing it to have a constant acceleration of 4 m/s^2 rightward. After 3s, what will be the velocity of the rocket ship? Answer using a coordinate system where rightward is positive.

Answer 1

here rocket starts from rest

It turns the booster and continue with constant acceleration

$a = 4 m/s^2$

now in order to find the final velocity we can use kinematics equation

$v_f = v_i + at$

here we know that

$v_i = 0$

t = 3 s

now plug in all data in above equation

$v_f = 0 + 4*3$

$v_f = 12 m/s$

so the rocket will move rightwards with speed 12 m/s after 3 s of boosters