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A ball is projected upward at time t = 0.00 s, from a point on a roof 70 m above the ground and experiences negligible air resistance. The ball rises, then falls and strikes the ground. The initial velocity of the ball is Consider all quantities as positive in the upward direction. The velocity of the ball when it is above the ground is closest to

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A ball is projected upward at time t = 0.00 s, from a point on a roof 70 m above the ground and experiences negligible air resistance. The ball rises, then falls and strikes the ground. The initial velocity of the ball is  Consider all quantities as positive in the upward direction. The velocity of the ball when it is  above the ground is closest to

anonymous · Answer

$$V_y^2=V_{0y}^2 +2a(y-y_0)$$ is the equation I am using but I am not getting a good answer. 

I am using y=39, $$y_0=70$$ $$V_{0y}=285$$ and a=-9.8