OMG PLEASE HELP GRADE 12 PHYSICS UNIVERSITY LEVEL
Physics

Tutor: None Selected  Time limit: 1 Day 
1. Rob throws a baseball upwards at 14.2 m/s. His friend, John, is sitting in a tree 4.5m above Rob.
a. Calculate how long it will take to reach John.
b. If John misses the ball as it moves upwards, how long will it take to reach John again.
Thank you for the opportunity to help you with your question!
1.Rob throws a baseball upwards at 14.2 m/s. His friend, John, is sitting in a tree 4.5m above Rob.
a. Calculate how long it will take to reach John.
b. If John misses the ball as it moves upwards, how long will it take to reach John again?
Given u = 14.2 m/s, h = 4.5m, g = 9.8m/s^{2}
a. S= ut – 0.5gt^{2 }
4.5 = 14.2t 4.9t^{2}
Rearranging and solving by quadratic equation
[img width="137" height="45" src="file:///C:/Users/NORMAX/AppData/Local/Temp/msohtmlclip1/01/clip_image001.gif" alt=" x=(b+/sqrt(b^24ac))/(2a). " v:shapes="Picture_x0020_1">
4.9t^{2} + 14.2t – 4.5 = 0
t = 0.36 sec
b. Max height, h = u^{2}/ 2g
h = 14.2^{2}/ 2*9.8 = 10.29 m
distance to john position= 10.294.5 = 5.79
for free fall, u=0
[img width="80" height="51" src="file:///C:/Users/NORMAX/AppData/Local/Temp/msohtmlclip1/01/clip_image002.png" alt="\ t =\ \sqrt {\frac{2d}{g}} " v:shapes="Picture_x0020_2">
t= sqrt( 2*5.79/9.8)
=1.08 sec.
Please let me know if you need any clarification. I'm always happy to answer your questions.
how did you find part b?
In part b, first i determined max height which is 10.29m, at max hight the ball wil freely fall with an initial velocity of 0. since john is 4.5 m from ground, the ball will fall through a distance of 5.8 m to john taking 1.08 seconds
time to reach max height is sqrt (2h/g) = 1.45 sec, time to reach john = 0.36 sec, time to reach max height after passing john = 1.45 0.36= 1.09 sec, so total time to back to john= 1.08 + 1.09 = 2.17 sec
answer to part b= 2.17 sec
Regards
In case you need more clarification or assistance in physics, kindly contact me. Thanks
Secure Information
Content will be erased after question is completed.