Question

A major-league pitcher throws a baseball toward home plate. The ball rotates at 1560 rpm, and it travels the 18.5 meters to the plate at an average translational speed of 40.2 m/s. How many revolutions does the ball make during this trip?

Answer 1

Answer:

no of revolutions  = 56.62 rev

Explanation:

given data

rotates = 1560 rpm

travels distance = 18.5 meters

speed = 40.2 m/s

solution

first we convert here rev/min to rev/sec

rotates = 1560 rpm = 1560  × 0.0167 = 26.052 rev/sec

we get here no of revolutions that is

no of revolutions = spin rotate ÷ time    ..........1

here time = distance ÷ speed

time = 18.5 ÷  40.2  

time = 0.4601 s

put value in equation 1 we get

no of revolutions = $\frac{26.052}{0.4601}$  

no of revolutions  = 56.62 rev