A small ball rolls horizontally off the edge of a tabletop that is 1.23 m high. It strikes the floor at a point 1.49 m horizontally away from the edge of the table. (a) How long is the ball in the air? (b) What is its speed at the instant it leaves ?

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Answer 1 · 2015-11-03T18:22:19

$(a). 0.5"s"$

$(b). 2.98"m/s"$

$(a).$

Taking the vertical component of the motion and setting the initial velocity equal to zero we get:

$s=1/2"g"t^2$

$:.t^2=(2s)/"g"=(2xx1.23)/(9.8)=0.251$

$:.t=sqrt(0.251)=0.5"s"$

$(b).$

The horizontal component of velocity is constant so:

$v=s/t=1.49/0.5=2.98"m/s"$