There is a 250-m-high cliff at Half Dome in Yosemite National Park in California. Suppose a boulder breaks loose from the top of this cliff. (a) How fast will it be going when it strikes the ground? (b) Assuming a reaction time of 0.300 s, how long will a tourist at the bottom have to get out of the way after hearing the sound of the rock breaking loose (neglecting the height of the tourist, which would become negligible anyway if hit)? The speed of sound is 335 m/s on this day.

Step-by-step solution 53PE Step 1 of 4 From the equation of motion, The final velocity of the object is, Here, s is the displacement, u is the initial v elocity and a is the acceleration of an object. Step 2 of 4 (a) Subs titute for s, 0 m/s for u a nd for a in formula for velocity. The velocity will be negative as rock is falling downwards. So, the final velocity of the rock when it strikes the ground is .