2. Un objeto es lanzado hacia arriba y luego de 4 s tiene una rapidez de 10 m/s. Determine con qué rapidez se lanzó. (g = 10 m/s2)

Apulley system lifts a 500-ib block 1.0 foot with an effort of only 50 ib. if the 50 ib moves 30 feet, calculate the efficiency of the pulley system. a. 30% b. 33% c. 70% d. 67%

Which of the following explains why it took so long for the public to accept the negative health effects of smoking? a)people were waiting for counter reasons, and those were presented.b)scientists had not completely finalized their results, which took 30 years.c)cigarettes were cheaply available and media channels were very inefficient.d)cigarette manufacturers were trying hard to bring an alternative into the market

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?