20. wile e. pushes a 76-kg boulder off of the 90-m cliff in an attempt to hit the roadrunner. what will the kinetic energy of the boulder be just before it hits the roadrunner? *note: this is a 2-step problem. include the unit in your answer.

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s