Question

an object is dropped off a cliff. how far will the object fall during the next 4s?

Answer 1

it's in constant acceleration since the only force on it is gravity

\(\Delta x=v_i\Delta t+\dfrac{1}{2}a\Delta t^2\)

\(\Delta x=0(4s)+\dfrac{1}{2}g(4s)^2\)

\(\Delta x=\dfrac{1}{2}(-9.8~m/s^2)(4s)^2\)

\(\Delta x=\dfrac{1}{2}(-9.8~m/s^2)(4s)^2=-78.4 ~m\)

it's negative because its in relation to the y axis.