13) A 1.2kg toy rocket is launched from its platform and reaches a height of 141m after 4.60s. If the rocket motor only produced an upwards acceleration for the first 1.20s before running out of fuel, what was its initial upwards acceleration? Neglect the effect of air resistance. (Hint: 141 m is not where the rocket reaches its maximum height. You don't know what the maximum height is in this question) (Answer: 41 m/s2)