Question

A toy rocket is shot straight up into the air with an initial speed of 45.0 m/s how long does it takes for the rocket to reach it's highest point ?

Answer 1

Explanation:

Given that,

Initial speed of the toy rocket, u = 45 m/s

Let t is the time taken by the rocket  to reach it's highest point. At the highest point the final speed of the rocket is 0. Using equation of kinematics to find the value of t as :

$v=u+at$

$u=-at$

Here, a = -g

$t=\dfrac{u}{a}$

$t=\dfrac{45}{9.8}$

t = 4.59 seconds

So, the rocket will take 4.59 seconds to reach its highest point. Hence, this is the required solution.

Answer 2

It will be
45/9.8 = t
4.6 sec