posted by Anonymous .
A rocket moves upward, starting from rest with an acceleration of 28.3 m/s2 for 5.50 s. It runs out of fuel at the end of the 5.50 s, but does not stop.
How high does it rise above the ground? Answer in units of m
h1=a*t^2 = 28.3*5.5^2=856.1 m Above gnd.
V1 = a*t = 28.3 * 5.5 = 155.7 m/s.
V = V1 + g*t = 0
155.7 - 9.8t = 0
-9.8t = -155.7
t = 15.9 s. To reach max ht.
h2 = V1*t + 0.5g*t^2
h2 = 155.7*15.9 - 4.9*15.9^2 = 1236 m
h = h1 + h2 = 856 + 1236 = 2092 m. Above gnd.