Question

A students who has a consistent throwing arm can throw a rock 30 m/s every time. Standing on a cliff, he throws a baseball 30 degrees up and then throws an identical baseball 30 degrees down. Which will have higher speed of impact on the ground? (Ignore wind resistance.)

A. Ball thrown up B. Ball thrown down C. Same

How much work is required to lift a 25 kg case of Giancoli books up a flight of stairs to the second floor that is 3 m above the round floor?

a. 1470 J

b. 39.2 J

c. 78.4 J

d. 735 J

Answer 1