Question

Elmer is standing on the edge of a 30.0 m high cliff. He throws a rock vertically with an initial velocity of 12.0 m/s? How high does the rock go?

Answer 1

7.34 m

Step-by-step explanation:

`u=\text{Initial velocity}=12\ \text{m/s}`

`v=\text{Final velocity}=0`

`a=g=\text{Acceleration due to gravity}=9.81\ \text{m/s}^2`

`s=\text{Displacement}`

From the equations of motion we have

`v^2-u^2=2as\\\Rightarrow s=(v^2-a^2)/(2a)\\\Rightarrow s=(0^2-12^2)/(2* -9.81)\\\Rightarrow s=7.34\ \text{m}`

The rock goes 7.34 m up from the point of release.

The rock goes
`30+7.34=37.34\ \text{m}` from the ground.