If you stand at the edge of a cliff that is 75 m high and throw a rock directly up into the air with a velocity of 20 m/s, at what time w ill the rock hit the ground?

Rock will hit the ground after a time of 6.45 s

initial velocity=20 m/s

initial displacement=Yo=75m

final displacement=0

using the kinematic equation

Y= Yo+ V t+ 1/2 gt²

0=75+20 t+1/2 (-9.8)t²

-4.9t²+20 t+75=0

This is a quadratic equation in t,s we use the quadratic formula

t=

t=6.45 s

0.863333

86%

hope this

the simple machine has three main features. they are:

fulcrum is the center point or pivot point of the machine. effort is input force/ applied force. load is external force/ output.

the keisha 's machine labels are

x : load

y: fulcrum

z: lever