Question

7. An astronaut shipwrecked on a distant planet with unknown characteristics is on top of a cliff, which he wishes to descend He does not know the acceleration due to gravity on the planet. and he has only a good watch with which to make measurements. He wants to learn the height of the cliff, and to do this, he makes two measurements (Fig. 2-2 ). First, he lets a rock fall from rest off the cliff edge; he finds that the rock takes 4.15 s to reach the distant ground. Second, he releases the rock from the same spot but tosses it upward so that it rises a height of what he estimates to be 2 m before it falls to the ground below. This time the rock takes 6.30 s to reach the ground. What is the height of the cliff? A FIGURE 2-2 Problem 7 15 m-tall huilding. What