A ball is dropped from a height of 49m above level ground.The height of the ball at time t is h(t)=49-4.9t^2 m.A light,which is also 49m above the ground,is 10m to the left of the ball's original position.As the ball descends, the shadow of the ball caused by the light moves across the ground.How fast is the shadow moving 2 seconds after the ball is dropped?
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