Suppose a rock is dropped off a cliff with an initial speed of 0 m/s. What is the rock's speed after 3 seconds, in m/s, if it encounters no air resistance?

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Answer 1 · 2018-03-06T00:27:33

I get #~~44.15 \ "m"#.

Well, we can use the falling objects equation, which states that

#d=1/2gt^2#

where #g# is the gravitational acceleration, #t# is the time in seconds.

So, plugging in values into the equation, we get

#d=1/2*9.81 \ "m/s"^2*9 \ "s"^2#

#=44.145 \ "m"#

#~~44.15 \ "m"#

So, the rock will approximately fall #44.15 \ "m"#.