1st question: A toy rocket is launched straight up from the top of a 15m high cliff v1 = 21m/s how long will it take the rocket to hit the ground after launch.

Question

Its about physics grade 11 kinemetics

Answer 1

Given u = -21m/s

H= 15 m

g= 9.8m/s2

Use H = ut +1/2 gt²

^{Plug in Values to get quadratic equation in t}

4.9t² -21t -15 = 0

solving for t ; t= 4.9 sec

ignore negative value of t