- #1

Lori

<Moderator's note: Moved from a technical forum and thus no template.>

So, i have this sample problem to reference to :

A stone is thrown from the top of a building with an initial velocity of 20 m/s downward. The top of the building is 60 m above the ground. How much time elapses between the instant of the release and the instant of impact with the ground? Here neglect air resistance.

I know that I'm suppose to solve for time with the given information. I have intitial y velocity which is 20 m/s and i know the y(height) is 60. Should i assume that Vf is 0 because it hits the floor? And, i use the Vy = Vyi + gt to get time about 2 seconds?

Or, should i find final velocity with vy^2 = vyi^2 + 2g(y) and THEN use vy to solve for t in Vy = vi + gt?

So, i have this sample problem to reference to :

A stone is thrown from the top of a building with an initial velocity of 20 m/s downward. The top of the building is 60 m above the ground. How much time elapses between the instant of the release and the instant of impact with the ground? Here neglect air resistance.

I know that I'm suppose to solve for time with the given information. I have intitial y velocity which is 20 m/s and i know the y(height) is 60. Should i assume that Vf is 0 because it hits the floor? And, i use the Vy = Vyi + gt to get time about 2 seconds?

Or, should i find final velocity with vy^2 = vyi^2 + 2g(y) and THEN use vy to solve for t in Vy = vi + gt?

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