A rock is thrown upward with a velocity of 26 meters per second from the top of a 43 meter high cliff, and it misses the cliff o

Question

4 years ago

14

n the way back down. When will the rock be 6 meters

1 answer:

mario62 [17] · Answer 1 · 2022-02-07T02:03:50+03:00

<h2>After 5.98 seconds the rock reaches 6 meter</h2>

Explanation:

We need to find when will the rock be 6 meters,

That is displacement = 6 - 26 = -20 m

We have equation of motion s = ut + 0.5 at²

Initial velocity, u = 26 m/s

Acceleration, a = -9.81 m/s²

Displacement, s = -20 m

Substituting

s = ut + 0.5 at²

-20 = 26 x t + 0.5 x -9.81 x t²

4.905 t² - 26 t -20 = 0

t = 5.98 s or t = -0.68 s

Time is always positive,

So after 5.98 seconds the rock reaches 6 meter