Hi Everyone! Like always, thank you for helping me figure out my last physics question! I greatly appreciate the help. Here are my next questions:(adsbygoogle = window.adsbygoogle || []).push({});

Q: Determine the speed at which a baseball must move in order for air resistance to be significant?

A: mg = ½ * Cd * A * pair * v^2 pair = density of air (1.2kg/m^3)

m = mass .1488kg

g = 9.8m/s^2

A=(pi*r^2)=3.14*.115m^2=.04154 m^2

Cd = .5 (sphere)

v= square root of ((2*.1488kg*9.8m/s^2)/(.5* 3.14*.04154 m^2* *1.2kg/m^3 ))

v = 36 m/s or 80mph

Q: If the ball were launched vertically into the air at this speed, how high will it go?

A: After finding the speed in the previous question; I would use this equation to find height:

KE = PE

PE = mgy

KE = 1/2mv^2

(½)(.1488kg)(36m/s)^2 = (.1488kg)(9.8m/s^2)y

66.122m=y

Q: how long will it be air born?

x = x0 + v0 *t + 1/2at^2

66.122m = 0m + 36m/s * t + -9.8m/s^2t

v =

I am stuck on this part and I don’t know if the rest of it is correct??? Please help!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Air drag

**Physics Forums | Science Articles, Homework Help, Discussion**