+0

Last Math Question

0
61
1
+171

I need helo on a VERY hard question (for me I guess)

John threw a ball straight up in the air at 30 meters per second, how far did it go up in 10 seconds?

PsychoBaker  Jun 17, 2017
Sort:

#1
+89578
+1

$$v_o=30\\ x_0=0\\ \ddot{x}=-9.8\\ \dot{x}=-9.8t+k_1\\ when\;\;t=0,\;\;\dot{x}=30\;\;so\;\;k_1=30\\ \dot{x}=-9.8t+30\\ x=\frac{-9.8t^2}{2}+30t+k_2\\ when\;\;t=0,\;\;x=0\;\;so\;\;k_2=0\\ x=-4.9t^2+30t\\~\\ Max\;\;reached \;\;when\;\;\dot{x}=0\\ \dot{x}=-9.8t+30=0\\ t=30/9.8\approx3.06sec\\ When\;\;t=3.06sec\\ x=-4.9*3.06^2+30*3.06\\ x\approx 45.9\;metres$$

I have not checked this fro errors but the method is correct :)

Melody  Jun 17, 2017

10 Online Users

We use cookies to personalise content and ads, to provide social media features and to analyse our traffic. We also share information about your use of our site with our social media, advertising and analytics partners.  See details