A small rocket is fired directly upwards with an initial velocity of 100m/s, How many seconds will it take

Question

to reach its maximum height?

Answer 1

Use the kinematic equation V = V0 + at defining up as positive.

Thus, t = (V-V0)/a

V0 is given as 100 m/s

At the top of the path V = 0

a = -9.81 m/s^2 (gravity)

Thus, t is about 10 seconds

Answer 2

t=(v-vo)/a
v=100m/sx10
a=9.81m/sx2