Saved Bookmarks
| 1. |
A rock is dropped off a cliff that's 80 m high. If it strikes the ground with an impact velocity of 40 m//s, what acceleration did it experience during its descent ? |
|
Answer» SOLUTION :If something is dropped, then that MEANS it has no initial velocity : `v_(0)= 0`. So, we're given `v_(0), DELTA s` and v, and we're asked for a. Since t is missing, we USE Big Five #5. `v^(2)= v_(0)^(2)+2a Delta s implies v^(2)= 2a Delta s ("since " v_(0)=0)` `a = (v^(2))/(2 Delta s)=((40 m//s)^(2))/(2(80 m))= 10 m//s^(2)`. |
|